Opencv On Android Studio: 使用获取手机摄像头数据并显示

最新推荐文章于 2025-07-01 09:03:11 发布

XYYHLark01

最新推荐文章于 2025-07-01 09:03:11 发布

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本文详细介绍了如何在Android Studio中集成OpenCV库，包括使用Java库进行摄像头数据处理和显示，以及通过CMake和JNI调用OpenCV函数的方法。涵盖了项目设置、权限配置、代码实现等关键步骤。

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Opencv On Android Studio: 使用获取手机摄像头数据并显示

1. 新建空项目
2. 将opencv的Java库作为Module导入

具体步骤为： File->new->Import，选择opencv-4.1.1-android-sdk\OpenCV-android-sdk\sdk(opencv-4.1.1-android-sdk从Opencv官网下载)

1. 修改opencv的build.gradle文件版本号

具体做法是，将文件列表上方的显示模式由Android切换至 Project，并展开文件列表。分别打开app\build.gradle文件和opencv411\build.gradle文件，将opencv411\build.gradle的几个版本号改成app\build.gradle文件里相同即可，然后在在文本域上点击 Try Again或工具栏图标。

1. 添加opencv411作为项目依赖module

打开File->Project Structure，在Modules里选择app，右侧进入Dependencies，点击加号，选择Module dependency。

1. AndroidMainfest.xml文件中添加Opencv权限

AndroidMainfest.xml的路径为myopencvTest\app\src\main\AndroidMainfest.xml

<uses-permission android:name="android.permission.CAMERA"/>
<uses-feature android:name="android.hardware.camera" android:required="false"/>
<uses-feature android:name="android.hardware.camera.autofocus" android:required="false"/>
<uses-feature android:name="android.hardware.camera.front" android:required="false"/>
<uses-feature android:name="android.hardware.camera.front.autofocus" android:required="false"/>

1. 修改activity_main.xml的内容

activity_main.xml 的路径为myopencvTest\app\src\main\res\layout\activity_main.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    xmlns:opencv="http://schemas.android.com/apk/res-auto"

    android:layout_width="match_parent"

    android:layout_height="match_parent" >



    <org.opencv.android.JavaCameraView

        android:layout_width="fill_parent"

        android:layout_height="fill_parent"

        android:visibility="gone"

        android:id="@+id/tutorial1_activity_java_surface_view"

        opencv:show_fps="true"

        opencv:camera_id="any" />



</FrameLayout>

1. 修改MainActivity.java的内容

内容如下所示：

public class MainActivity extends CameraActivity implements CameraBridgeViewBase.CvCameraViewListener2 {

    private static final String TAG = "OCVSample::Activity";



    private CameraBridgeViewBase mOpenCvCameraView;

    private boolean              mIsJavaCamera = true;

    private MenuItem             mItemSwitchCamera = null;



    private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {

        @Override

        public void onManagerConnected(int status) {

            switch (status) {

                case LoaderCallbackInterface.SUCCESS:

                {

                    Log.i(TAG, "OpenCV loaded successfully");

                    mOpenCvCameraView.enableView();

                } break;

                default:

                {

                    super.onManagerConnected(status);

                } break;

            }

        }

    };



    public MainActivity() {

        Log.i(TAG, "Instantiated new " + this.getClass());

    }



    /** Called when the activity is first created. */

    @Override

    public void onCreate(Bundle savedInstanceState) {

        Log.i(TAG, "called onCreate");

        super.onCreate(savedInstanceState);

        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);



        setContentView(R.layout.activity_main);



        mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.tutorial1_activity_java_surface_view);



        mOpenCvCameraView.setVisibility(SurfaceView.VISIBLE);



        mOpenCvCameraView.setCvCameraViewListener(this);

    }



    @Override

    public void onPause()

    {

        super.onPause();

        if (mOpenCvCameraView != null)

            mOpenCvCameraView.disableView();

    }



    @Override

    public void onResume()

    {

        super.onResume();

        if (!OpenCVLoader.initDebug()) {

            Log.d(TAG, "Internal OpenCV library not found. Using OpenCV Manager for initialization");

            OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_3_0_0, this, mLoaderCallback);

        } else {

            Log.d(TAG, "OpenCV library found inside package. Using it!");

            mLoaderCallback.onManagerConnected(LoaderCallbackInterface.SUCCESS);

        }

    }



    @Override

    protected List<? extends CameraBridgeViewBase> getCameraViewList() {

        return Collections.singletonList(mOpenCvCameraView);

    }



    public void onDestroy() {

        super.onDestroy();

        if (mOpenCvCameraView != null)

            mOpenCvCameraView.disableView();

    }



    public void onCameraViewStarted(int width, int height) {

    }



    public void onCameraViewStopped() {

    }



    public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {

        return inputFrame.rgba();

    }

}

1. 参考网址

https://www.jianshu.com/p/6e16c0429044

Android Studio 使用CMake并用jni调用opencv函数

1. 将CMakelists.txt复制到工程app目录之下，如下图所示

1. 在CMakelists.txt中添加使用opencv的so库及cpp文件，并包含头文件

修改后的CMakelists.txt如下所示：

cmake_minimum_required(VERSION 3.4.1)



# OpenCV stuff

set(OpenCV_DIR D:/ProgramData/opencv/OpenCV-android-sdk/sdk/native/jni)

find_package(OpenCV REQUIRED)



add_library( # Sets the name of the library.

             native-lib



             # Sets the library as a shared library.

             SHARED



             # Provides a relative path to your source file(s).

             # Associated headers in the same location as their source

             # file are automatically included.

             src/main/cpp/native-lib.cpp )



find_library( # Sets the name of the path variable.

              log-lib



              # Specifies the name of the NDK library that

              # you want CMake to locate.

              log )



include_directories(D:/ProgramData/opencv/OpenCV-android-sdk/sdk/native/jni/include)

add_library( lib_opencv SHARED IMPORTED )

set_target_properties(

        lib_opencv

        PROPERTIES IMPORTED_LOCATION

        D:/ProgramData/opencv/OpenCV-android-sdk/sdk/native/libs/armeabi-v7a/libopencv_java4.so

)





target_link_libraries( # Specifies the target library.

                       native-lib



                       # OpenCV lib



                        ${lib_opencv}



                       # Links the target library to the log library

                       # included in the NDK.

                       ${log-lib} )

1. 修改gradle配置，将gradle与CMakelists.txt的原生库关联，并指定ABI

其中，添加的模块为：

ndk{
            abiFilters 'x86', 'x86_64', 'armeabi-v7a', 'arm64-v8a'
        }
        externalNativeBuild {
            cmake {
                cppFlags "-frtti -fexceptions"
                abiFilters 'x86', 'x86_64', 'armeabi-v7a', 'arm64-v8a'
            }
        }
配置gradle与CMakelist文件关联,内容如下所示：

externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
        }
    }

修改后的app/build.gradle内容如下所示：

apply plugin: 'com.android.application'



android {

    compileSdkVersion 29

    buildToolsVersion "29.0.1"

    defaultConfig {

        applicationId "com.example.testapplication"

        minSdkVersion 26

        targetSdkVersion 29

        versionCode 1

        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"



        ndk{

            abiFilters 'x86', 'x86_64', 'armeabi-v7a', 'arm64-v8a'

        }

        externalNativeBuild {

            cmake {

                cppFlags "-frtti -fexceptions"

                abiFilters 'x86', 'x86_64', 'armeabi-v7a', 'arm64-v8a'

            }

        }

    }



    externalNativeBuild {

        cmake {

            path "CMakeLists.txt"

        }

    }



    buildTypes {

        release {

            minifyEnabled false

            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'

        }

    }



}

dependencies {

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

    implementation 'androidx.appcompat:appcompat:1.0.2'

    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'

    implementation 'com.google.android.material:material:1.0.0'

    testImplementation 'junit:junit:4.12'

    androidTestImplementation 'androidx.test:runner:1.2.0'

    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'

    compile project(path: ':opencv411sdk')

}

1. MainActivity.java中添加自定义的C++库

System.loadLibrary("native-lib");

1. 调用jni函数

定义：

public native void salt(long matAddrGray, int nbrElem);

调用：

public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {

    Mat matGray = inputFrame.gray();

    salt(matGray.getNativeObjAddr(), 100);

    Log.i(TAG, "onCameraFrame");

    return matGray;

}