Android+openCV人脸检测2(静态图片)

前几篇文章中有提到对openCV环境配置，这里再重新梳理导入和使用openCV进行简单的人脸检测（包括使用级联分类器）

一 首先导入openCVLibrary320

二 设置gradle的sdk版本号与当前项目一致

    compileSdkVersion 26
    buildToolsVersion "26.0.2"

    defaultConfig {
        minSdkVersion 14
        targetSdkVersion 26
    }

三 新建 jniLibs 目录

在 app/src/main 目录下 与 java 目录同级，新建 jniLibs 目录

把 OpenCV-android-sdk-3.2/sdk/native/libs 目录下的所有文件夹内容拷贝到 jniLibs 目录

四 加载so包

    private static String strLibraryName = "opencv_java3"; // 不需要添加前缀 libopencv_java3

    static {
        try {
            Log.e("loadLibrary", strLibraryName);
            System.loadLibrary(strLibraryName);
            //System.loadLibrary(Core.NATIVE_LIBRARY_NAME); // couldn't find "libopencv_java320.so"
        } catch (UnsatisfiedLinkError e) {
            Log.e("loadLibrary", "Native code library failed to load.\n" + e);
        } catch (Exception e) {
            Log.e("loadLibrary", "Exception: " + e);
        }
    }

五 添加xml级联分类器

在导入的openCVLibrary320模块中，找到 src/main/res 目录，新建raw文件夹。

在 OpenCV-android-sdk-3.2/sdk/etc 目录下，存放的则是训练好的分类器。把 haarcascades 目录和 lbpcascades 目录内的所有xml文件拷贝到 raw目录中。

六 配置权限

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />

    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.FLASHLIGHT" />

完成以上步骤，就可以使用opencv了。

使用openCV

首先创建检测器

    mCascadeClassifier = createDetector(context, R.raw.haarcascade_frontalface_alt);

    /**
     * 创建检测器
     *
     * @param context 上下文
     * @param id      级联分类器ID
     * @return 检测器
     */
    private CascadeClassifier createDetector(Context context, int id) {
        CascadeClassifier javaDetector;
        InputStream is = null;
        FileOutputStream os = null;
        try {
            is = context.getResources().openRawResource(id);
            File cascadeDir = context.getDir("cascade", Context.MODE_PRIVATE);
            File cascadeFile = new File(cascadeDir, id + ".xml");
            os = new FileOutputStream(cascadeFile);

            byte[] buffer = new byte[4096];
            int bytesRead;
            while ((bytesRead = is.read(buffer)) != -1) {
                os.write(buffer, 0, bytesRead);
            }

            javaDetector = new CascadeClassifier(cascadeFile.getAbsolutePath());
            if (javaDetector.empty()) {
                javaDetector = null;
            }

            boolean delete = cascadeDir.delete();
            return javaDetector;
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        } finally {
            try {
                if (null != is) {
                    is.close();
                }
                if (null != os) {
                    os.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

检测人脸方法：

    /**
     * 目标检测 图片
     *
     * @param gray   灰度图像
     * @param object 识别结果的容器
     * @return
     */
    public Rect[] detectObjectImage(Mat gray, MatOfRect object) {
        mCascadeClassifier.detectMultiScale(gray,object);
        return object.toArray();
    }

detectFace 整个函数：

    private void detectFace() {
        try {
            // bitmapToMat
            Mat toMat = new Mat();
            Utils.bitmapToMat(bitmap, toMat);
            Mat copyMat = new Mat();
            toMat.copyTo(copyMat); // 复制

            // togray
            Mat gray = new Mat();
            Imgproc.cvtColor(toMat, gray, Imgproc.COLOR_RGBA2GRAY);

            MatOfRect mRect = new MatOfRect();
            Rect[] object = mFaceDetector.detectObjectImage(gray, mRect);

            Log.e("objectLength", object.length + "");

            int maxRectArea = 0 * 0;
            Rect maxRect = null;

            int facenum = 0;
            // Draw a bounding box around each face.
            for (Rect rect : object) {
                Imgproc.rectangle(
                        toMat,
                        new Point(rect.x, rect.y),
                        new Point(rect.x + rect.width, rect.y + rect.height),
                        new Scalar(255, 0, 0), 3);
                ++facenum;
                // 找出最大的面积
                int tmp = rect.width * rect.height;
                if (tmp >= maxRectArea) {
                    maxRectArea = tmp;
                    maxRect = rect;
                }
            }

            rectBitmap = null;
            if (facenum != 0) {
                // 剪切最大的头像
                Log.e("剪切的长宽", String.format("高:%s,宽:%s", maxRect.width, maxRect.height));
                Rect rect = new Rect(maxRect.x, maxRect.y, maxRect.width, maxRect.height);
                Mat rectMat = new Mat(copyMat, rect);  // 从原始图像拿
                rectBitmap = Bitmap.createBitmap(rectMat.cols(), rectMat.rows(), Bitmap.Config.ARGB_8888);
                Utils.matToBitmap(rectMat, rectBitmap);
            }

            textView.setText(String.format("检测到%1$d个人脸", facenum));
            Utils.matToBitmap(toMat, bitmap);

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

    }

附所有代码：

package com.myproject.facedetection.ui;

import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Gravity;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import com.myproject.facedetection.R;
import com.myproject.facedetection.entity.CustomImageButton;
import com.opencvlib.ObjectDetector;

import org.opencv.android.Utils;
import org.opencv.core.Mat;
import org.opencv.core.MatOfRect;
import org.opencv.core.Point;
import org.opencv.core.Rect;
import org.opencv.core.Scalar;
import org.opencv.imgproc.Imgproc;

import java.io.File;

public class FaceDetectionOpenCVActivity extends AppCompatActivity {
    private ObjectDetector mFaceDetector;

    private static String CAMERAIMAGENAME = "image.jpg";
    private CustomImageButton imageButton;
    private CustomImageButton imageButton2;
    private TextView textView;
    private Bitmap bitmap;
    private Bitmap rectBitmap;
    private Bitmap resizeBitmap;
    private Toast toast;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_face_detection_opencv);
        textView = (TextView) findViewById(R.id.tv_face);
        imageButton = (CustomImageButton) findViewById(R.id.iv_face);
        imageButton.setGravity(Gravity.CENTER_HORIZONTAL | Gravity.CENTER_VERTICAL);
        imageButton2 = (CustomImageButton) findViewById(R.id.iv_face2);
        imageButton2.setGravity(Gravity.CENTER_HORIZONTAL | Gravity.CENTER_VERTICAL);

        mFaceDetector = new ObjectDetector(this, R.raw.haarcascade_frontalface_alt, 6, 0.2F, 0.2F, new Scalar(255, 0, 0, 255));
    }

    /**
     * 点击添加照片事件
     *
     * @param v
     */
    public void onClick(View v) {

        int bt_id = v.getId();
        switch (bt_id) {
            case R.id.addPic:
                // 添加照片
                // 打开本地相册
                Intent intent1 = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
                startActivityForResult(intent1, 101);
                break;

            case R.id.takePhoto:
                // 拍照
                // 打开本地相机
                Intent intent2 = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
                Uri imageUri = Uri.fromFile(new File(Environment.getExternalStorageDirectory(), CAMERAIMAGENAME));
                intent2.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
                startActivityForResult(intent2, 102);

                break;

            case R.id.back:
                this.finish();
                break;

            default:
                break;
        }

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        // 加判断 不选择照片或者不拍照时不闪退
        //Log.e("data", String.valueOf(data));
        //if (data == null)
        //return;

        bitmap = null;
        switch (requestCode) {
            // 选择图片库的图片
            case 101:
                if (resultCode == RESULT_OK) {
                    try {
                        Uri uri = data.getData();
                        bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), uri);

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

            // 表示调用本地照相机拍照
            case 102:
                if (resultCode == RESULT_OK) {
                    //Bundle bundle = data.getExtras();
                    //bm = (Bitmap) bundle.get("data");
                    bitmap = BitmapFactory.decodeFile(Environment.getExternalStorageDirectory() + "/" + CAMERAIMAGENAME);

                }
                break;
            default:
                break;
        }

        Log.e("bitmap", String.valueOf(bitmap));

        if (bitmap == null) {
            toast = Toast.makeText(FaceDetectionOpenCVActivity.this, "未选择图像", Toast.LENGTH_SHORT);
            toast.show();
            return;
        }

        // 识别图片 并画框
        detectFace();

        // 将照片剪裁 bitmap将被释放重新赋值
        int ibWidth = imageButton.getWidth();
        int ibHeight = imageButton.getHeight();
        resizeBitmap = imageButton.resizeBitmap(bitmap, ibWidth, ibHeight);

        imageButton.setBitmap(resizeBitmap);
        imageButton2.setBitmap(rectBitmap);

    }

    private void detectFace() {
        try {
            // bitmapToMat
            Mat toMat = new Mat();
            Utils.bitmapToMat(bitmap, toMat);
            Mat copyMat = new Mat();
            toMat.copyTo(copyMat); // 复制

            // togray
            Mat gray = new Mat();
            Imgproc.cvtColor(toMat, gray, Imgproc.COLOR_RGBA2GRAY);

            MatOfRect mRect = new MatOfRect();
            Rect[] object = mFaceDetector.detectObjectImage(gray, mRect);

            Log.e("objectLength", object.length + "");

            int maxRectArea = 0 * 0;
            Rect maxRect = null;

            int facenum = 0;
            // Draw a bounding box around each face.
            for (Rect rect : object) {
                Imgproc.rectangle(
                        toMat,
                        new Point(rect.x, rect.y),
                        new Point(rect.x + rect.width, rect.y + rect.height),
                        new Scalar(255, 0, 0), 3);
                ++facenum;
                // 找出最大的面积
                int tmp = rect.width * rect.height;
                if (tmp >= maxRectArea) {
                    maxRectArea = tmp;
                    maxRect = rect;
                }
            }

            rectBitmap = null;
            if (facenum != 0) {
                // 剪切最大的头像
                Log.e("剪切的长宽", String.format("高:%s,宽:%s", maxRect.width, maxRect.height));
                Rect rect = new Rect(maxRect.x, maxRect.y, maxRect.width, maxRect.height);
                Mat rectMat = new Mat(copyMat, rect);  // 从原始图像拿
                rectBitmap = Bitmap.createBitmap(rectMat.cols(), rectMat.rows(), Bitmap.Config.ARGB_8888);
                Utils.matToBitmap(rectMat, rectBitmap);
            }

            textView.setText(String.format("检测到%1$d个人脸", facenum));
            Utils.matToBitmap(toMat, bitmap);

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

    }

}

FaceDetectionOpenCVActivity

package com.opencvlib;

import android.content.Context;

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 org.opencv.objdetect.Objdetect;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * Created by think-hxr on 17-10-12.
 */

public class ObjectDetector {
    private CascadeClassifier mCascadeClassifier;
    private int mMinNeighbors;
    private float mRelativeObjectWidth;
    private float mRelativeObjectHeight;
    private Scalar mRectColor;

    /**
     * 构造方法
     *
     * @param context              上下文
     * @param id                   级联分类器ID
     * @param minNeighbors         连续几帧确认目标
     * @param relativeObjectWidth  最小宽度屏占比
     * @param relativeObjectHeight 最小高度屏占比
     * @param rectColor            画笔颜色
     */
    public ObjectDetector(Context context, int id, int minNeighbors, float relativeObjectWidth, float relativeObjectHeight, Scalar rectColor) {
        context = context.getApplicationContext();
        mCascadeClassifier = createDetector(context, id);
        mMinNeighbors = minNeighbors;
        mRelativeObjectWidth = relativeObjectWidth;
        mRelativeObjectHeight = relativeObjectHeight;
        mRectColor = rectColor;
    }

    /**
     * 创建检测器
     *
     * @param context 上下文
     * @param id      级联分类器ID
     * @return 检测器
     */
    private CascadeClassifier createDetector(Context context, int id) {
        CascadeClassifier javaDetector;
        InputStream is = null;
        FileOutputStream os = null;
        try {
            is = context.getResources().openRawResource(id);
            File cascadeDir = context.getDir("cascade", Context.MODE_PRIVATE);
            File cascadeFile = new File(cascadeDir, id + ".xml");
            os = new FileOutputStream(cascadeFile);

            byte[] buffer = new byte[4096];
            int bytesRead;
            while ((bytesRead = is.read(buffer)) != -1) {
                os.write(buffer, 0, bytesRead);
            }

            javaDetector = new CascadeClassifier(cascadeFile.getAbsolutePath());
            if (javaDetector.empty()) {
                javaDetector = null;
            }

            boolean delete = cascadeDir.delete();
            return javaDetector;
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        } finally {
            try {
                if (null != is) {
                    is.close();
                }
                if (null != os) {
                    os.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 目标检测 视频
     *
     * @param gray   灰度图像
     * @param object 识别结果的容器
     * @return 检测到的目标位置集合
     */
    public Rect[] detectObject(Mat gray, MatOfRect object) {
        // 使用Java人脸检测
        mCascadeClassifier.detectMultiScale(
                gray, // 要检查的灰度图像
                object, // 检测到的人脸
                1.1, // 表示在前后两次相继的扫描中，搜索窗口的比例系数。默认为1.1即每次搜索窗口依次扩大10%;
                mMinNeighbors, // 默认是3 控制误检测，表示默认几次重叠检测到人脸，才认为人脸存在
                Objdetect.CASCADE_SCALE_IMAGE,
                getSize(gray, mRelativeObjectWidth, mRelativeObjectHeight), // 目标最小可能的大小
                gray.size()); // 目标最大可能的大小

        return object.toArray();
    }

    /**
     * 目标检测 图片
     *
     * @param gray   灰度图像
     * @param object 识别结果的容器
     * @return
     */
    public Rect[] detectObjectImage(Mat gray, MatOfRect object) {
        mCascadeClassifier.detectMultiScale(gray,object);
        return object.toArray();
    }

    /**
     * 根据屏占比获取大小
     *
     * @param gray                 gray
     * @param relativeObjectWidth  最小宽度屏占比
     * @param relativeObjectHeight 最小高度屏占比
     * @return 大小
     */
    private Size getSize(Mat gray, float relativeObjectWidth, float relativeObjectHeight) {
        Size size = gray.size();
        int cameraWidth = gray.cols();
        int cameraHeight = gray.rows();
        int width = Math.round(cameraWidth * relativeObjectWidth);
        int height = Math.round(cameraHeight * relativeObjectHeight);
        size.width = 0 >= width ? 0 : (cameraWidth < width ? cameraWidth : width); // width [0, cameraWidth]
        size.height = 0 >= height ? 0 : (cameraHeight < height ? cameraHeight : height); // height [0, cameraHeight]
        return size;
    }

    /**
     * 获取画笔颜色
     *
     * @return 颜色
     */
    public Scalar getRectColor() {
        return mRectColor;
    }
}

ObjectDetector

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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="com.myproject.facedetection.ui.FaceDetectionOpenCVActivity">

    <com.myproject.facedetection.entity.CustomImageButton
        android:id="@+id/iv_face"
        android:layout_width="0dp"
        android:layout_height="460dp"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="10dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        tools:layout_editor_absoluteY="10dp" />

    <com.myproject.facedetection.entity.CustomImageButton
        android:id="@+id/iv_face2"
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:layout_marginRight="10dp"
        app:layout_constraintRight_toRightOf="parent"
        tools:layout_editor_absoluteY="10dp" />

    <TextView
        android:id="@+id/tv_face"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp"
        android:text="未检测到人脸"
        android:textColor="@color/colorAccent"
        app:layout_constraintBottom_toTopOf="@+id/ll1"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent" />

    <LinearLayout
        android:id="@+id/ll1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent">

        <Button
            android:id="@+id/takePhoto"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="5dp"
            android:layout_weight="1"
            android:onClick="onClick"
            android:text="拍照(CV)"
            android:textSize="16sp"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent" />

        <Button
            android:id="@+id/addPic"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="5dp"
            android:layout_weight="1"
            android:onClick="onClick"
            android:text="选择图片(CV)"
            android:textSize="16sp"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent" />

        <Button
            android:id="@+id/back"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="0dp"
            android:layout_weight="1"
            android:onClick="onClick"
            android:text="返回(CV)"
            android:textSize="16sp"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent" />
    </LinearLayout>

</android.support.constraint.ConstraintLayout>

activity_face_detection_opencv.xml