【Android】OpenCV4Android开发技巧

Android开发技巧

1、根据res路径来读取OpenCV的xml人脸检测文件

private CascadeClassifier cascadeClassifier; //加载人脸检测xml try {     // Copy the resource into a temp file so OpenCV can load it     InputStream is = getResources().openRawResource(R.raw.haarcascade_frontalface_alt);     File cascadeDir = getDir("cascade", Context.MODE_PRIVATE);     File mCascadeFile = new File(cascadeDir, "haarcascade_frontalface_alt.xml");     FileOutputStream os = new FileOutputStream(mCascadeFile);     byte[] buffer = new byte[4096];     int bytesRead;     while ((bytesRead = is.read(buffer)) != -1) {         os.write(buffer, 0, bytesRead);     }     is.close();     os.close();     // Load the cascade classifier     cascadeClassifier = new CascadeClassifier(mCascadeFile.getAbsolutePath()); } catch (Exception e) {     Log.e("OpenCVActivity", "Error loading cascade", e); }

 

2、菜单操作Menu

res-menu建菜单menu_main.xml xml version="1.0" encoding="utf-8"?> xmlns:android="http://schemas.android.com/apk/res/android">             android:id = "@+id/add_item"         android:title = "Add"/>             android:id = "@+id/remove_item"         android:title = "Remove"/>             android:id = "@+id/delete_item"         android:title = "Delete"/> onOptionsItemSelected()方法内实现 @Override public boolean onOptionsItemSelected(MenuItem item){     switch(item.getItemId()){         case R.id.add_item:             Toast.makeText(this, "You Clicked Add!!", Toast.LENGTH_SHORT).show();             break;         case R.id.remove_item:             Toast.makeText(this, "You Clicked Remove!", Toast.LENGTH_SHORT).show();             break;         case R.id.delete_item:             Toast.makeText(this, "You Clicked Delete!", Toast.LENGTH_SHORT).show();             break;         default:             break;     }     return true; }   //创建菜单 public boolean onCreateOptionsMenu(Menu menu){     getMenuInflater().inflate(R.menu.main, menu);     return true; }

 

3、Button按钮控件/子Activity开启

方式一： findViewById(R.id.btn_online_demo).setOnClickListener(MainActivity.this); findViewById(R.id.btn_offline_demo).setOnClickListener(MainActivity.this); @Override public void onClick(View v) {    Intent intent = null;    switch (v.getId()) {    case R.id.btn_online_demo:       intent = new Intent(MainActivity.this, OnlineFaceDemo.class);       startActivity(intent);       break;    case R.id.btn_offline_demo:       intent = new Intent(MainActivity.this, OfflineFaceDemo.class);       startActivity(intent);       break;    default:       break;    } } 方式二： buttonFirst = (Button)findViewById(R.id.button1); buttonFirst.setOnClickListener(new View.OnClickListener() {     @Override     public void onClick(View v) {         Toast.makeText(MainActivity.this, "You Clicked Button1!", Toast.LENGTH_SHORT).show();         Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);         photoPickerIntent.setType("image/*");         startActivityForResult(photoPickerIntent, PICTURE_CHOOSE);     } });

 

4、

private File mPictureFile; …… // 设置相机拍照后照片保存路径 mPictureFile = new File(Environment.getExternalStorageDirectory(),       "picture" + System.currentTimeMillis()/1000 + ".jpg"); // 启动拍照,并保存到临时文件 Intent mIntent = new Intent(); mIntent.setAction(MediaStore.ACTION_IMAGE_CAPTURE); mIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(mPictureFile)); mIntent.putExtra(MediaStore.Images.Media.ORIENTATION, 0); startActivityForResult(mIntent, FaceUtil.REQUEST_CAMERA_IMAGE);

 

5、在Bitmap上绘制区域Canvas（科大讯飞）

private void drawFaceRects(FaceRect[] faces) {    Paint paint = new Paint();    paint.setColor(Color.YELLOW);    paint.setStrokeWidth(Math.max(mImage.getWidth(), mImage.getHeight()) / 100f);    paint.setStyle(Style.STROKE);    Bitmap bitmap = Bitmap.createBitmap(mImage.getWidth(), mImage.getHeight(), Config.ARGB_8888);    Canvas canvas = new Canvas(bitmap);    canvas.drawBitmap(mImage, new Matrix(), null);       for (FaceRect face: faces) {       canvas.drawRect(face.bound, paint);             if (null != face.point) {          for (Point p: face.point) {             canvas.drawPoint(p.x, p.y, paint);          }       }    }       ((ImageView) findViewById(R.id.offline_img)).setImageBitmap(bitmap); }

 

6、保存Bitmap图片到指定路径

//保存图片 public static void saveBitmap(Bitmap bm, String picName) {    File f = new File("/storage/emulated/0/Pictures/", picName);    if (f.exists()) {       f.delete();    }    try {       FileOutputStream out = new FileOutputStream(f);       bm.compress(Bitmap.CompressFormat.PNG, 90, out);       out.flush();       out.close();    } catch (FileNotFoundException e) {       // TODO Auto-generated catch block       e.printStackTrace();    } catch (IOException e) {       // TODO Auto-generated catch block       e.printStackTrace();    } }

 

7、随机生成指定长度的字符串

//length用户要求产生字符串的长度 public static String getRandomString(int length){    String str="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";    Random random=new Random();    StringBuffer sb=new StringBuffer();    for(int i=0;i;i++){       int number=random.nextInt(62);       sb.append(str.charAt(number));    }    return sb.toString(); }

 

8、进度对话框的使用

// 进度对话框 private ProgressDialog mProDialog; mProDialog = new ProgressDialog(this); mProDialog.setCancelable(true); mProDialog.setTitle("请稍后"); mProDialog.setOnCancelListener(new OnCancelListener() {    @Override    public void onCancel(DialogInterface dialog) {       // cancel进度框时,取消正在进行的操作       if (null != mFaceRequest) {          mFaceRequest.cancel();       }    } });   mProDialog.setMessage("注册中..."); mProDialog.show();   if (null != mProDialog) {    mProDialog.dismiss(); }

 

9、RadioGroup单选按钮控件

RadioGroup alignGruop = (RadioGroup) findViewById(R.id.align_mode); alignGruop.setOnCheckedChangeListener(new OnCheckedChangeListener() {     @Override     public void onCheckedChanged(RadioGroup arg0, int arg1) {         switch (arg1) {             case R.id.detect:                 isAlign = 0;                 break;             case R.id.align:                 isAlign = 1;                 break;             default:                 break;         }     } });

 

10、Camera操作

private Camera mCamera; private int mCameraId = CameraInfo.CAMERA_FACING_FRONT; // Camera nv21格式预览帧的尺寸，默认设置640*480 private int PREVIEW_WIDTH = 640; private int PREVIEW_HEIGHT = 480; // 预览帧数据存储数组和缓存数组 private byte[] nv21; private byte[] buffer; // 缩放矩阵 private Matrix mScaleMatrix = new Matrix(); // 加速度感应器，用于获取手机的朝向 private Accelerometer mAcc;   nv21 = new byte[PREVIEW_WIDTH * PREVIEW_HEIGHT * 2]; buffer = new byte[PREVIEW_WIDTH * PREVIEW_HEIGHT * 2]; mAcc = new Accelerometer(VideoDemo.this);   @Override public void onClick(View v) {     // 只有一个摄相头，不支持切换     if (Camera.getNumberOfCameras() == 1) {         showTip("只有后置摄像头，不能切换");         return;     }     closeCamera();     if (CameraInfo.CAMERA_FACING_FRONT == mCameraId) {         mCameraId = CameraInfo.CAMERA_FACING_BACK;     } else {         mCameraId = CameraInfo.CAMERA_FACING_FRONT;     }     openCamera(); }   private void openCamera() {     if (null != mCamera) {         return;     }     if (!checkCameraPermission()) {         showTip("摄像头权限未打开，请打开后再试");         mStopTrack = true;         return;     }     // 只有一个摄相头，打开后置     if (Camera.getNumberOfCameras() == 1) {         mCameraId = CameraInfo.CAMERA_FACING_BACK;     }     try {         mCamera = Camera.open(mCameraId);         if (CameraInfo.CAMERA_FACING_FRONT == mCameraId) {             showTip("前置摄像头已开启，点击可切换");         } else {             showTip("后置摄像头已开启，点击可切换");         }     } catch (Exception e) {         e.printStackTrace();         closeCamera();         return;     }     Parameters params = mCamera.getParameters();     params.setPreviewFormat(ImageFormat.NV21);     params.setPreviewSize(PREVIEW_WIDTH, PREVIEW_HEIGHT);     mCamera.setParameters(params);     // 设置显示的偏转角度，大部分机器是顺时针90度，某些机器需要按情况设置     mCamera.setDisplayOrientation(90);     mCamera.setPreviewCallback(new PreviewCallback() {         @Override         public void onPreviewFrame(byte[] data, Camera camera) {             System.arraycopy(data, 0, nv21, 0, data.length);         }     });     try {         mCamera.setPreviewDisplay(mPreviewSurface.getHolder());         mCamera.startPreview();     } catch (IOException e) {         e.printStackTrace();     } }     private void closeCamera() {     if (null != mCamera) {         mCamera.setPreviewCallback(null);         mCamera.stopPreview();         mCamera.release();         mCamera = null;     } } private boolean checkCameraPermission() {     int status = checkPermission(permission.CAMERA, Process.myPid(), Process.myUid());     if (PackageManager.PERMISSION_GRANTED == status) {         return true;     }     return false; } // 长按SurfaceView 500ms后松开，摄相头聚集 mFaceSurface.setOnTouchListener(new OnTouchListener() {     @Override     public boolean onTouch(View v, MotionEvent event) {         switch (event.getAction()) {             case MotionEvent.ACTION_DOWN:                 mLastClickTime = System.currentTimeMillis();                 break;             case MotionEvent.ACTION_UP:                 if (System.currentTimeMillis() - mLastClickTime > 500) {                     mCamera.autoFocus(null);                     return true;                 }                 break;             default:                 break;         }         return false;     } });

 

11、读取指定路径的Bitmap

Bitmap bitmap1 = BitmapFactory.decodeResource(getResources(), R.drawable.img_01);

 

12、double转成String

String str_x = Double.toString(pt.x); String str_y = Double.toString(pt.y);

 

13、创建线程

HandlerThreaddetectThread = null; Handler detectHandler = null;   detectThread = new HandlerThread("detect"); detectThread.start(); detectHandler = new Handler(detectThread.getLooper());   detectHandler.post(new Runnable() {     @Override     public void run() {         final Bitmap bit = getFaceInfoBitmap(faceinfo, img);         runOnUiThread(new Runnable() {             @Override             public void run() {                 imageView.setImageBitmap(bit);                 System.gc();                 textView.setText("Waiting runOnUiThread ...");             }         });     } });

 

14、复制Bitmap

Bitmap tmp; tmp = oribitmap.copy(Bitmap.Config.ARGB_8888, true);

 

15、Toast提示功能

Toast.makeText(MainActivity.this, "You Clicked Button1!", Toast.LENGTH_SHORT).show();

 

16、选择图片，并显示

Intent photoPickerIntent = new Intent(Intent.ACTION_PICK); photoPickerIntent.setType("image/*"); startActivityForResult(photoPickerIntent, PICTURE_CHOOSE);   @Override protected void onActivityResult(int requestCode, int resultCode, Intent intent) {     super.onActivityResult(requestCode, resultCode, intent);     if (requestCode == PICTURE_CHOOSE) {         if (intent != null) {             try {                 //加载图片并显示                 ContentResolver resolver = getContentResolver();                 Uri originalUri = intent.getData();//获得图片的uri                 img = MediaStore.Images.Media.getBitmap(resolver, originalUri);                 imageView.setImageBitmap(img);                 //获取图片的路径                 Cursor cursor = getContentResolver().query(intent.getData(), null, null, null, null);                 cursor.moveToFirst();                 int idx = cursor.getColumnIndex(ImageColumns.DATA);                 String fileSrc = cursor.getString(idx);                 textViewDebug.setText("Picture:" + fileSrc);                 textView.setText("图片加载成功！");                 buttonDetect.setVisibility(View.VISIBLE);                 }catch (IOException e) {                 textView.setText("TAG-->Error" + e.toString());                 }         }         else {             textViewDebug.setText("intent == null");         }     } }//onActivityResult()

 

17、NDK使用方法：http://blog.csdn.net/taily_duan/article/details/52484583

public static native int[] grayProc(int[] pixels, int w, int h); static {     System.loadLibrary("gray-process"); }   bmp = BitmapFactory.decodeResource(getResources(), R.drawable.pic); imageView.setImageBitmap(bmp);   int w = bmp.getWidth(); int h = bmp.getHeight(); int[] pixels = new int[w*h]; bmp.getPixels(pixels, 0, w, 0, 0, w, h); int[] resultInt = grayProc(pixels, w, h); Bitmap resultImg = Bitmap.createBitmap(w, h, Config.ARGB_8888); resultImg.setPixels(resultInt, 0, w, 0, 0, w, h); imageView.setImageBitmap(resultImg);

 

18、跳转子页面

Button buttonThree = (Button)findViewById(R.id.button3); buttonThree.setOnClickListener(new View.OnClickListener() {     @Override     public void onClick(View v) {         Toast.makeText(MainActivity.this, "跳转到子页面!", Toast.LENGTH_SHORT).show();         Intent intent = new Intent(MainActivity.this, Main2Activity.class);         startActivity(intent);         finish();     } });

 

19、ListView显示：图片+文字

ListView listView = (ListView) findViewById(R.id.listView1); Map, Object> item1 = new HashMap, Object>(); item1.put("image", R.drawable.vae); item1.put("name", "duanjjwei"); Map, Object> item2 = new HashMap, Object>(); item2.put("image", R.drawable.smyh); item2.put("name", "zhuangguangli"); List, Object>> data = new ArrayList, Object>>(); data.add(item1); data.add(item2); SimpleAdapter simpleAdapter = new SimpleAdapter(this, data,       R.layout.activity_main_item, new String[] { "image", "name" },       new int[] { R.id.imageView1, R.id.textView1 }); listView.setAdapter(simpleAdapter);

 

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OpenCV for Android开发技巧

1、实现CvCameraViewListener 需要实现的虚函数，定义BaseLoaderCallback回调函数接口，并实现这个类中的onManagerConnected()方法

private CameraBridgeViewBase mOpenCvCameraView;   private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(MainActivity.this) {     @Override     public void onManagerConnected(int status) {         switch (status) {             case LoaderCallbackInterface.SUCCESS:             {                 Log.i(TAG, "OpenCV loaded successfully");                 imageMat=new Mat();                 //enable camera                 mOpenCvCameraView.enableView();             } break;             default:             {                 super.onManagerConnected(status);             } break;         }     } };

 

2、onResume()中加载OpenCV库（OpenCVLoader）；

@Override public void onResume() {     super.onResume();     if (!OpenCVLoader.initDebug()) {         Log.d("OpenCV", "Internal OpenCV library not found. Using OpenCV Manager for initialization");         OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_10, this, mLoaderCallback);     } else {         Log.d("OpenCV", "OpenCV library found inside package. Using it!");         mLoaderCallback.onManagerConnected(LoaderCallbackInterface.SUCCESS);     } }

 

 

3、Mat变量创建

Mat mRgba  = new Mat(height, width, CvType.CV_8UC4);//创建 mRgba.release();//释放

 

4、根据res路径来读取OpenCV的xml人脸检测文件

private CascadeClassifier cascadeClassifier; //加载人脸检测xml try {     // Copy the resource into a temp file so OpenCV can load it     InputStream is = getResources().openRawResource(R.raw.haarcascade_frontalface_alt);     File cascadeDir = getDir("cascade", Context.MODE_PRIVATE);     File mCascadeFile = new File(cascadeDir, "haarcascade_frontalface_alt.xml");     FileOutputStream os = new FileOutputStream(mCascadeFile);     byte[] buffer = new byte[4096];     int bytesRead;     while ((bytesRead = is.read(buffer)) != -1) {         os.write(buffer, 0, bytesRead);     }     is.close();     os.close();     // Load the cascade classifier     cascadeClassifier = new CascadeClassifier(mCascadeFile.getAbsolutePath()); } catch (Exception e) {     Log.e("OpenCVActivity", "Error loading cascade", e); }

 

5、人脸检测

private CascadeClassifier cascadeClassifier;     //检测并显示     MatOfRect faces = new MatOfRect();     if (cascadeClassifier != null) {         cascadeClassifier.detectMultiScale(mGray, faces, 1.1, 2, 2, new Size(mGray.height()/5, mGray.height()/5), new Size());     }     Rect[] facesArray = faces.toArray();     for (int i = 0; i length; i++) {         Core.rectangle(mShow, facesArray[i].tl(), facesArray[i].br(), new Scalar(0, 255, 0, 255), 3);         Point pt = new Point();         pt.x = facesArray[i].br().x;         pt.y = facesArray[i].br().y;         String str_x = Double.toString(pt.x);         String str_y = Double.toString(pt.y);         String str = str_x + ", " + str_y;         Core.putText(mShow,str, pt, Core.FONT_HERSHEY_SIMPLEX, 1, new Scalar(255,23,0),2);     }

 

6、Bitmap与Mat转换/OpenCV彩色转灰度

//---------------------OpenCV处理------------------------ Mat mat_src = new Mat(bmp.getWidth(), bmp.getHeight(), CvType.CV_8UC4); Utils.bitmapToMat(bmp, mat_src); Mat mat_gray = new Mat(bmp.getWidth(), bmp.getHeight(), CvType.CV_8UC1); Imgproc.cvtColor(mat_src, mat_gray, Imgproc.COLOR_BGRA2GRAY, 1); Bitmap bmp_dst = Bitmap.createBitmap(mat_gray.cols(), mat_gray.rows(), Bitmap.Config.ARGB_8888 ); Utils.matToBitmap(mat_gray, bmp_dst);

 

7、图片的缩放/或使用resize

//缩放图片大小 public static Bitmap getScaledBitmap(Bitmap m_img, float sx, float sy) {    Matrix matrix = new Matrix();    matrix.postScale(sx, sy);    Bitmap rst = Bitmap.createBitmap(m_img, 0, 0, m_img.getWidth(), m_img.getHeight(), matrix, true);    return rst; }

 

8、Mat中截取Rect部分的图片

Rect[] facesArray = faces.toArray(); Mat copyMat = mGray.submat(facesArray[i]);

 

9、使用Core.putText在图像上输入文字

String str = str_x + ", " + str_y + " S1:" + c1 + " S2:"+ c2; Core.putText(mat_src,str, pt, Core.FONT_HERSHEY_SIMPLEX, 1, new Scalar(255,23,0),2);

 

10、Mat、Bitmap、IplImage相互转换

//Mat转成Bitmap public Bitmap MatToBitmap(Mat src) {     Bitmap bitmap = Bitmap.createBitmap(src.width(), src.height(), Bitmap.Config.ARGB_8888);     Utils.matToBitmap(src, bitmap);     return bitmap; } //Bitmap转换成Mat public Mat bitmapToMat(Bitmap bitmap) {     Mat rgbMat = new Mat();     Utils.bitmapToMat(bitmap, rgbMat);     return rgbMat; } //IplImage转换成Bitmap public Bitmap IplImageToBitmap(opencv_core.IplImage iplImage) {     Bitmap bitmap = null;     bitmap = Bitmap.createBitmap(iplImage.width(), iplImage.height(), Bitmap.Config.ARGB_8888);     bitmap.copyPixelsFromBuffer(iplImage.getByteBuffer());     return bitmap; } //Bitmap转换成IplImage public opencv_core.IplImage bitmapToIplImage(Bitmap bitmap) {     opencv_core.IplImage iplImage;     iplImage = opencv_core.IplImage.create(bitmap.getWidth(), bitmap.getHeight(), opencv_core.IPL_DEPTH_8U, 4);     bitmap.copyPixelsToBuffer(iplImage.getByteBuffer());     return iplImage; }

 

11、图像的灰度直方图

public double CmpPic(opencv_core.IplImage Image1, opencv_core.IplImage Image2) {     int l_bins = 20;     int hist_size[] = {l_bins};     float v_ranges[] = {0, 100};     float ranges[][] = {v_ranges};     opencv_core.IplImage imageArr1[] = {Image1};     opencv_core.IplImage imageArr2[] = {Image2};     opencv_imgproc.CvHistogram Histogram1 = opencv_imgproc.CvHistogram.create(1, hist_size, opencv_imgproc.CV_HIST_ARRAY, ranges, 1);     opencv_imgproc.CvHistogram Histogram2 = opencv_imgproc.CvHistogram.create(1, hist_size, opencv_imgproc.CV_HIST_ARRAY, ranges, 1);     cvCalcHist(imageArr1, Histogram1, 0, null);     cvCalcHist(imageArr2, Histogram2, 0, null);     cvNormalizeHist(Histogram1, 100.0);     cvNormalizeHist(Histogram2, 100.0);     return cvCompareHist(Histogram1, Histogram2, opencv_imgproc.CV_COMP_CORREL); }

 

12、RGB转换成HSV

int nHeight = bitmap.getHeight()/10; int nWidth  = bitmap.getWidth()/10; Mat mat_small = new Mat(nHeight, nWidth, CvType.CV_8UC4); Imgproc.resize(mat_src, mat_small, new Size(nWidth, nHeight)); Mat mat_gray = new Mat(mat_small.cols(), mat_small.rows(), CvType.CV_8UC1); Imgproc.cvtColor(mat_small, mat_gray, Imgproc.COLOR_BGRA2GRAY, 1); //------------------------------------------------------------------- Mat frame = new Mat(mat_small.cols(), mat_small.rows(), CvType.CV_8UC4); mat_small.copyTo(frame); Mat frameHSV = new Mat(mat_small.cols(), mat_small.rows(), CvType.CV_8UC3);;   // hsv空间 Mat mask = new Mat(mat_small.cols(), mat_small.rows(), CvType.CV_8UC1); Mat dst = new Mat(mat_small.cols(), mat_small.rows(), CvType.CV_8UC3); // 输出图像 //dst.copyTo(frame); // 中值滤波，去除椒盐噪声 Imgproc.medianBlur(frame, frame, 5); Imgproc.cvtColor(frame, frameHSV, Imgproc.COLOR_RGB2HSV, 3); Mat dstTemp1 = new Mat(mat_small.cols(), mat_small.rows(), CvType.CV_8UC1); Mat dstTemp2 = new Mat(mat_small.cols(), mat_small.rows(), CvType.CV_8UC1); // 对HSV空间进行量化，得到二值图像，亮的部分为手的形状 Core.inRange(frameHSV, new Scalar(0, 30, 30), new Scalar(40, 170, 256), dstTemp1); Core.inRange(frameHSV, new Scalar(156, 30, 30), new Scalar(180, 170, 256), dstTemp2); Core.bitwise_or(dstTemp1, dstTemp2, mask); //dstTemp1.copyTo(mask); // 形态学操作，去除噪声，并使手的边界更加清晰 Mat element = Imgproc.getStructuringElement(Imgproc.MORPH_RECT, new Size(3, 3)); Imgproc.erode(mask, mask, element); Imgproc.morphologyEx(mask, mask, Imgproc.MORPH_OPEN, element); Imgproc.dilate(mask, mask, element); Imgproc.morphologyEx(mask, mask, Imgproc.MORPH_CLOSE, element); frame.copyTo(dst, mask);

 

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