as中opencv的使用 人脸检测

做一个预研 开始学习下opencv的使用 先从导入项目开始

1、下载

进入官网（http://opencv.org/）下载OpenCV4Android并解压。目录结构如下图所示。

我下载了 opencv-3.2.0-android-sdk。zip

其中，sdk目录即是我们开发opencv所需要的类库；samples目录中存放着若干opencv应用示例（包括人脸检测等），可为我们进行android下的opencv开发提供参考

2、将OpenCV引入Android Studio

创建一个新项目  在Android Studio中选择File->Import Module，找到OpenCV解压的路径，选择sdk/java文件夹。

或者

看见 出来

3、更新build.gradle信息  选择 opencv里面的build。gradle 把

compileSdkVersion 25buildToolsVersion "25.0.3"defaultConfig {    minSdkVersion 15    targetSdkVersion 25}

信息改成和版本一致的

点击 open Module Settings

把 openlib 加到app的项目依赖里面

复制libs文件夹到项目中

在OpenCV的解压包中，将sdk-->native-->libs文件夹复制，粘贴在Project视图下app-->src-->main目录下，并将其重命名为jniLibs。

就可以了 

直接网上找段代码 看看可以使用不

import android.content.Context;import android.content.Intent;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.util.Log;import android.view.View;import android.view.Window;import android.view.WindowManager;import android.widget.Button;import android.widget.RelativeLayout;import org.opencv.android.CameraBridgeViewBase;import org.opencv.android.JavaCameraView;import org.opencv.android.OpenCVLoader;import org.opencv.core.Core;import org.opencv.core.CvType;import org.opencv.core.Mat;import org.opencv.core.MatOfRect;import org.opencv.core.Rect;import org.opencv.core.Scalar;import org.opencv.core.Size;import org.opencv.objdetect.CascadeClassifier;import java.io.File;import java.io.FileOutputStream;import java.io.InputStream;public class MainActivity extends AppCompatActivity        implements CameraBridgeViewBase.CvCameraViewListener {    private CameraBridgeViewBase openCvCameraView;    private CascadeClassifier cascadeClassifier;    //图像人脸小于高度的多少就不检测    private int absoluteFaceSize;    //临时图像对象    private Mat matLin;    //最终图像对象    private Mat mat;    //前置摄像头    public static int CAMERA_FRONT = 0;    //后置摄像头    public static int CAMERA_BACK = 1;    private int camera_scene = CAMERA_BACK;    private void initializeOpenCVDependencies() {        try {            // Copy the resource into a temp file so OpenCV can load it            InputStream is = getResources().openRawResource(R.raw.lbpcascade_frontalface);            File cascadeDir = getDir("cascade", Context.MODE_PRIVATE);            File mCascadeFile = new File(cascadeDir, "lbpcascade_frontalface.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();            // 加载人脸特征文件            cascadeClassifier = new CascadeClassifier(mCascadeFile.getAbsolutePath());        } catch (Exception e) {            Log.e("OpenCVActivity", "Error loading cascade", e);        }        // And we are ready to go        openCvCameraView.enableView();    }    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);//        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);        getWindow().clearFlags(                WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);        getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);        requestWindowFeature(Window.FEATURE_NO_TITLE);// 设置横屏模式以及全屏模式        setContentView(R.layout.activity_main);        final RelativeLayout relativeLayout = (RelativeLayout) findViewById(R.id.relative);        openCvCameraView = new JavaCameraView(this, CameraBridgeViewBase.CAMERA_ID_FRONT);        openCvCameraView.setCvCameraViewListener(this);

 final Button button = new Button(MainActivity.this);        button.setText("切换摄像头");        button.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                if (camera_scene == CAMERA_FRONT) {//如果是前置摄像头就切换成后置
                    relativeLayout.removeAllViews();                    openCvCameraView.disableView();                    openCvCameraView = null;                    cascadeClassifier = null;
                    openCvCameraView = new JavaCameraView(MainActivity.this, CameraBridgeViewBase.CAMERA_ID_BACK);                    openCvCameraView.setCvCameraViewListener(MainActivity.this);
                    openCvCameraView.setCameraIndex(CameraBridgeViewBase.CAMERA_ID_BACK);//后置摄像头                    camera_scene = CAMERA_BACK;
                    relativeLayout.addView(openCvCameraView);                    relativeLayout.addView(button);
                    initializeOpenCVDependencies();                } else {
                    relativeLayout.removeAllViews();                    openCvCameraView.disableView();                    openCvCameraView = null;                    cascadeClassifier = null;
                    openCvCameraView = new JavaCameraView(MainActivity.this, CameraBridgeViewBase.CAMERA_ID_FRONT);                    openCvCameraView.setCvCameraViewListener(MainActivity.this);
                    openCvCameraView.setCameraIndex(CameraBridgeViewBase.CAMERA_ID_FRONT);//前置摄像头                    camera_scene = CAMERA_FRONT;
                    relativeLayout.addView(openCvCameraView);                    relativeLayout.addView(button);
                    initializeOpenCVDependencies();                }            }        });
        relativeLayout.addView(openCvCameraView);        relativeLayout.addView(button);
        if (camera_scene == CAMERA_FRONT) {            openCvCameraView.setCameraIndex(CameraBridgeViewBase.CAMERA_ID_FRONT);//前置摄像头        } else if (camera_scene == CAMERA_BACK) {            openCvCameraView.setCameraIndex(CameraBridgeViewBase.CAMERA_ID_BACK);//后置摄像头        }    }    @Override    public void onCameraViewStarted(int width, int height) {        matLin = new Mat(height, width, CvType.CV_8UC4);//临时图像        // 人脸小于高度的百分之30就不检测        absoluteFaceSize = (int) (height * 0.3);    }    @Override    public void onCameraViewStopped() {    }    @Override    public Mat onCameraFrame(Mat aInputFrame) {        //转置函数,将图像翻转（顺时针90度）        Core.transpose(aInputFrame, matLin);        //在手机横屏时方向正常 在竖屏时图片向左转了90度 小米手机        if (camera_scene == CAMERA_FRONT) {//前置摄像头//            //转置函数,将图像翻转（对换）//            Core.flip(matLin, aInputFrame, 1); 这个方法有问题 参数位置前后不一样 导致黑屏//            //转置函数,将图像反转（对换 修改0或1）横屏方向正常 竖屏左转了90度            Core.flip(aInputFrame, matLin, 1);            mat = matLin;        } else if (camera_scene == CAMERA_BACK) {//后置摄像头            //转置函数,将图像翻转（对换）//            Core.flip(matLin, aInputFrame, 1);            mat = aInputFrame;        }        MatOfRect faces = new MatOfRect();        Log.i("123456", "absoluteFaceSize = " + absoluteFaceSize);        // Use the classifier to detect faces        if (cascadeClassifier != null) {            cascadeClassifier.detectMultiScale(mat, faces, 1.1, 1, 1,                    new Size(absoluteFaceSize, absoluteFaceSize), new Size());        }        // 检测出多少个        Rect[] facesArray = faces.toArray();        for (int i = 0; i < facesArray.length; i++) {            Log.i("123456", "facesArray[i].tl()坐上坐标 == " + facesArray[i].tl() + "      facesArray[i].br() == 右下坐标" + facesArray[i].br());
//3.2的sdk把core进行了拆分 细化 有的方法在别的类中           //  Core.rectangle(mat, facesArray[i].tl(), facesArray[i].br(), new Scalar(0, 255, 0, 255), 3);
//根据坐标绘制了一个方框Imgproc.rectangle(mat, facesArray[i].tl(), facesArray[i].br(), new Scalar(0, 255, 0, 255), 3);
        }        return mat;    }    @Override    public void onResume() {        super.onResume();        if (!OpenCVLoader.initDebug()) {            Log.e("log_wons", "OpenCV init error");            // Handle initialization error        }        initializeOpenCVDependencies();        //OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_6, this, mLoaderCallback);    }}

布局放一个id为relative全屏的空的RelativeLayout 就可以了

AndroidManifest中加上

<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" />

6.0以上的动态权限就不加了 手动去权限管理里面开一下就行了 

这里一直遇到启动了摄像头 黑屏问题 最后发现是出图像翻转处理的问题 加了注释  但是在手机上实测 横屏方向正常 在竖屏时图像左转了90度 很蛋疼 不过总算出来了  

先这样吧 检测出来了    识别是否一致 继续研究