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 25
buildToolsVersion "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_fronta
12e60
lface.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}}@Overridepublic 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);}@Overridepublic void onCameraViewStopped() {}@Overridepublic 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 facesif (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-featureandroid:name="android.hardware.camera"android:required="false" /><uses-featureandroid:name="android.hardware.camera.autofocus"android:required="false" /><uses-featureandroid:name="android.hardware.camera.front"android:required="false" /><uses-featureandroid: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