基于Android studio3.6的JNI教程之ncnn之语义分割ENet

代码链接：

https://github.com/watersink/enet-as-linux

本代码可以在模拟器下进行跑。

 

环境：

Android studio 3.6

Sdk：android10 api 29

Ndk：r15c

Ncnn：20200226

Opencv：Opencv3.4.1 android sdk

 

Linux下的代码测试：

mkdir build
cd build
cmake ..
make
./enet

运行效果，

 

Android开始：

(1)新建工程，

New->New Project->选择Native c++  ->工程名enet->c++11

(2)app/src/cpp下面增加opencv和ncnn的头文件，include

(3)app/src/main下面增加ncnn 和opencv的静态库文件和动态库文件，

(4)app/src/main下面增加模型文件assets

(5)修改布局文件，app/src/main/res/layout/ activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <LinearLayout
        android:id="@+id/btn_ll"
        android:layout_alignParentBottom="true"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <Button
            android:id="@+id/use_photo"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="选图"/>
        <Button
            android:id="@+id/detect_photo"
            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="分割"/>
    </LinearLayout>


    <ImageView
        android:id="@+id/show_image"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@id/btn_ll"
        android:layout_alignParentTop="true"
        android:layout_marginTop="1dp"
        android:layout_marginBottom="-1dp" />
</RelativeLayout>

(6) app/src/main/java/com/example/enet增加ENET类，

public class ENET {


    public native boolean Init(byte[] param, byte[] bin);
    public native float[] Process(Bitmap bitmap);
    // Used to load the 'native-lib' library on application startup.

    static {
        System.loadLibrary("ENET");
    }
}

(7) app/src/main/cpp/enet-jni.cpp实现其jni方法，

extern "C"
JNIEXPORT jboolean JNICALL
Java_com_example_enet_ENET_Init(JNIEnv *env, jobject thiz, jbyteArray param, jbyteArray bin) {

    // TODO: implement Init()
    ncnn::Mat ncnn_param;
    ncnn::Mat ncnn_bin;


    // init param
    {
        int len = env->GetArrayLength(param);
        ncnn_param.create(len, (size_t) 1u);
        env->GetByteArrayRegion(param, 0, len, (jbyte *) ncnn_param);
    }

    // init bin
    {
        int len = env->GetArrayLength(bin);
        ncnn_bin.create(len, (size_t) 1u);
        env->GetByteArrayRegion(bin, 0, len, (jbyte *) ncnn_bin);
    }

    ncnn_net = new ENET(ncnn_param,ncnn_bin);
    return JNI_TRUE;


}

extern "C"
JNIEXPORT jfloatArray JNICALL
Java_com_example_enet_ENET_Process(JNIEnv *env, jobject thiz, jobject bitmap) {
    // TODO: implement Process()

    // ncnn from bitmap
    ncnn::Mat in;
    {
        AndroidBitmapInfo info;
        AndroidBitmap_getInfo(env, bitmap, &info);

        int width = info.width;
        int height = info.height;

        if (info.format != ANDROID_BITMAP_FORMAT_RGBA_8888)
            return NULL;

        void* indata;
        AndroidBitmap_lockPixels(env, bitmap, &indata);


        // 把像素转换成data，并指定通道顺序
        // 因为图像预处理每个网络层输入的数据格式不一样一般为300*300 128*128等等所以这类需要一个resize的操作可以在cpp中写，也可以是java读入图片时有个resize操作
        //in = ncnn::Mat::from_pixels_resize((const unsigned char*)indata, ncnn::Mat::PIXEL_RGBA2RGB, width, height,300,300);
        in = ncnn::Mat::from_pixels(static_cast<const unsigned char *>(indata), ncnn::Mat::PIXEL_RGBA2BGR, width, height);

        // 下面一行为debug代码
        __android_log_print(ANDROID_LOG_DEBUG, "ENetJniIn", "enet_process_has_input1, in.w: %d; in.h: %d in.c:%d ", in.w, in.h,in.c);
        //AndroidBitmap_unlockPixels(env, bitmap);
    }

    {

        ncnn::Mat out = ncnn_net->process(in);

        __android_log_print(ANDROID_LOG_DEBUG, "ENetJniIn", "enet_process_has_output, in.w: %d; in.h: %d in.c:%d ", out.w, out.h,out.c);
        int output_wsize = out.w;
        int output_hsize = out.h;
        //输出整理
        float *output[output_wsize * output_hsize];   // float类型
        for(int i = 0; i< out.h; i++) {
            for (int j = 0; j < out.w; j++) {
                output[i*output_wsize + j] = &out.row(
                        i)[j];
            }
        }
        //建立float数组 长度为 output_wsize * output_hsize,如果只是ouput_size相当于只有一行的out的数据那就是一个object检测数据
        jfloatArray jOutputData = env->NewFloatArray(output_wsize * output_hsize);
        if (jOutputData == nullptr) return nullptr;
        env->SetFloatArrayRegion(jOutputData, 0,  output_wsize * output_hsize,
                               reinterpret_cast<const jfloat *>(*output));
        return jOutputData;
    }


}

(8) app/src/main/java/com/example/enet中MainActivity做具体的调用实现，

public class MainActivity extends AppCompatActivity {

    private ENET enet = new ENET(); //java接口实例化　下面直接利用java函数调用NDK c++函数


    private Bitmap yourSelectedImage = null;

    private static final int SELECT_IMAGE = 1;
    private static final String TAG = MainActivity.class.getName();
    private ImageView show_image;
    private boolean load_result = false;
    private int[] ddims = {1, 3, 512, 288}; //这里的维度的值要和train model的input 一一对应



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);



        try
        {
            initENet();//初始化模型
            Log.e("MainActivity", "initENet ok");
        } catch (IOException e) {
            Log.e("MainActivity", "initENet error");
        }


        init_view();//检测+view画图

    }


    // initialize view
    private void init_view() {
        show_image = (ImageView) findViewById(R.id.show_image);
        Button use_photo = (Button) findViewById(R.id.use_photo);
        use_photo.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                Intent i = new Intent(Intent.ACTION_PICK);
                i.setType("image/*");
                startActivityForResult(i, SELECT_IMAGE);
            }
        });


        Button detect_photo = (Button) findViewById(R.id.detect_photo);
        detect_photo.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {

                if (yourSelectedImage == null)
                    return;

                predict_image(yourSelectedImage);
            }

        });



    }



    private void initENet() throws IOException {
        byte[] param = null;
        byte[] bin = null;
        {
            //用io流读取二进制文件，最后存入到byte[]数组中
            InputStream assetsInputStream = getAssets().open("enet_512288.param.bin");// param：  网络结构文件
            int available = assetsInputStream.available();
            param = new byte[available];
            int byteCode = assetsInputStream.read(param);
            assetsInputStream.close();
        }
        {
            //用io流读取二进制文件，最后存入到byte上，转换为int型
            InputStream assetsInputStream = getAssets().open("enet_512288.bin");//bin：   model文件
            int available = assetsInputStream.available();
            bin = new byte[available];
            int byteCode = assetsInputStream.read(bin);
            assetsInputStream.close();
        }

        load_result = enet.Init(param, bin);// 再将文件传入java的NDK接口(c++ 代码中的init接口 )
        Log.d("load model", "ENet_load_model_result:" + load_result);
    }

    

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data)
    {
        super.onActivityResult(requestCode, resultCode, data);

        if (resultCode == RESULT_OK && null != data) {
            Uri selectedImage = data.getData();

            try
            {
                if (requestCode == SELECT_IMAGE) {
                    Bitmap bitmap = decodeUri(selectedImage);

                    Bitmap rgba = bitmap.copy(Bitmap.Config.ARGB_8888, true);

                    // resize to 512x288
                    yourSelectedImage = Bitmap.createScaledBitmap(rgba, ddims[2], ddims[3], false);

                    show_image.setImageBitmap(yourSelectedImage);
                }
            }
            catch (FileNotFoundException e)
            {
                Log.e("MainActivity", "FileNotFoundException");
                return;
            }
        }
    }

    private Bitmap decodeUri(Uri selectedImage) throws FileNotFoundException
    {
        // Decode image size
        BitmapFactory.Options o = new BitmapFactory.Options();
        o.inJustDecodeBounds = true;
        BitmapFactory.decodeStream(getContentResolver().openInputStream(selectedImage), null, o);

        // The new size we want to scale to
        final int REQUIRED_SIZE = 600;

        // Find the correct scale value. It should be the power of 2.
        int width_tmp = o.outWidth, height_tmp = o.outHeight;
        int scale = 1;
        while (true) {
            if (width_tmp / 2 < REQUIRED_SIZE
                    || height_tmp / 2 < REQUIRED_SIZE) {
                break;
            }
            width_tmp /= 2;
            height_tmp /= 2;
            scale *= 2;
        }

        // Decode with inSampleSize
        BitmapFactory.Options o2 = new BitmapFactory.Options();
        o2.inSampleSize = scale;
        return BitmapFactory.decodeStream(getContentResolver().openInputStream(selectedImage), null, o2);
    }


    //  predict image
    private void predict_image(Bitmap bmp) {
        // picture to float array
        Bitmap rgba = bmp.copy(Bitmap.Config.ARGB_8888, true);
        // resize
        Bitmap input_bmp = Bitmap.createScaledBitmap(rgba, ddims[2], ddims[3], false);


        try {
            // Data format conversion takes too long
            // Log.d("inputData", Arrays.toString(inputData));
            long start = System.currentTimeMillis();
            // get predict result
            float[] result = enet.Process(input_bmp);
            // time end
            long end = System.currentTimeMillis();
            Log.d(TAG, "origin predict result:" + Arrays.toString(result));
            long time = end - start;
            Log.d("result length", "length of result: " + String.valueOf(result.length));


            // 画布配置
            Canvas canvas = new Canvas(input_bmp);
            //图像上画矩形
            Paint paint = new Paint();
            //continue to draw rect
            Log.d(TAG, "result :" + result.length);
            Log.d(TAG, "result :" + Arrays.toString(result));
            for(int num = 0; num < result.length; num++){

                // 画框
                int row =num%ddims[2];
                int col = num/ddims[2];

                if (result[num]==1){
                    paint.setColor(Color.RED);
                    paint.setStyle(Paint.Style.STROKE);//不填充
                    canvas.drawCircle(row, col, 1,  paint);
                }

                if (result[num]==2){
                    paint.setColor(Color.BLUE);
                    paint.setStyle(Paint.Style.STROKE);//不填充
                    canvas.drawCircle(row, col, 1,  paint);
                }
                if (result[num]==3){
                    paint.setColor(Color.GREEN);
                    paint.setStyle(Paint.Style.STROKE);//不填充
                    canvas.drawCircle(row, col, 1,  paint);

                }

            }

            show_image.setImageBitmap(input_bmp);


        } catch (Exception e) {
            e.printStackTrace();
        }
    }


}

(9) app/src/main/cpp下面修改CMakeLists

cmake_minimum_required(VERSION 3.4.1)
include_directories(include)
file(GLOB ENET_SRC *.h
        *.cpp)
set(ENET_COMPILE_CODE ${ENET_SRC})
add_library(libopencv_java3 SHARED IMPORTED)
set_target_properties(libopencv_java3 PROPERTIES IMPORTED_LOCATION
        ${CMAKE_SOURCE_DIR}/../jniLibs/${ANDROID_ABI}/libopencv_java3.so)

add_library(libncnn STATIC IMPORTED )
set_target_properties(libncnn
        PROPERTIES IMPORTED_LOCATION
        ${CMAKE_SOURCE_DIR}/../jniLibs/${ANDROID_ABI}/libncnn.a)
add_library( # Sets the name of the library.
        ENET ## 为生成.so的文字最好直接和.c名字一样,需要更改
        # Sets the library as a shared library.
        SHARED
        # Provides a relative path to your source file(s).
        ${ENET_COMPILE_CODE})##cpp文件的name
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 )
target_link_libraries( # Specifies the target library.
                       ENET
                       libncnn
                       libopencv_java3
                       jnigraphics
                       android
                       # Links the target library to the log library
                       # included in the NDK.
                       ${log-lib} )

(10) app/src/下面修改build.gradle，增加下面的设置，

externalNativeBuild {
            cmake {
                arguments "-DANDROID_TOOLCHAIN=clang"
                cFlags "-fopenmp -O2 -fvisibility=hidden -fomit-frame-pointer -fstrict-aliasing -ffunction-sections -fdata-sections -ffast-math "
                cppFlags "-fopenmp -O2 -fvisibility=hidden -fvisibility-inlines-hidden -fomit-frame-pointer -fstrict-aliasing -ffunction-sections -fdata-sections -ffast-math "
                arguments "-DANDROID_STL=c++_shared", "-DANDROID_CPP_FEATURES=rtti exceptions"
                cppFlags ""
                cppFlags "-std=c++11"
                cppFlags "-frtti"
                cppFlags "-fexceptions"
            }
        }
        ndk {
            abiFilters 'armeabi-v7a'// , 'arm64-v8a' //,'x86', 'x86_64', 'armeabi'
            stl "gnustl_static"
        }

整体目录结构：

最终效果：