缺点是精度不高，识别信息很少，只有眼睛的识别

MainActivity.java

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PointF;
import android.media.FaceDetector;
import android.os.Bundle;
import android.util.Log;
import android.view.ViewGroup;
import android.widget.ImageView;public class MainActivity extends Activity {private final int MAX_FACES = 5;    //最大可识别的人脸数private ImageView mIv;private Bitmap mFaceBitmap;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);//创建一个ImageView，加载到Activity视图上mIv = new ImageView(this);setContentView(mIv, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));//要进行人脸识别的图片mFaceBitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.face);mIv.setImageBitmap(mFaceBitmap);//因为这是一个耗时的操作，所以放到另一个线程中运行new Thread(new Runnable() {@Overridepublic void run() {FaceDetector.Face[] faces = new FaceDetector.Face[MAX_FACES];//格式必须为RGB_565才可以识别Bitmap bmp = mFaceBitmap.copy(Bitmap.Config.RGB_565, true);//返回识别的人脸数int faceCount = new FaceDetector(bmp.getWidth(), bmp.getHeight(), MAX_FACES).findFaces(bmp, faces);bmp.recycle();bmp = null;Log.e("tag", "识别的人脸数:" + faceCount);if (faceCount > 0) {final Bitmap bitmap = parseBitmap(faces, faceCount);//显示处理后的图片mIv.post(new Runnable() {@Overridepublic void run() {mIv.setImageBitmap(bitmap);}});}}}).start();}/*** 在人脸上画矩形*/private Bitmap parseBitmap(FaceDetector.Face[] faces, int faceCount){Bitmap bitmap = Bitmap.createBitmap(mFaceBitmap.getWidth(), mFaceBitmap.getHeight(), Bitmap.Config.ARGB_8888);Canvas canvas = new Canvas(bitmap);Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);mPaint.setColor(Color.YELLOW);mPaint.setStrokeWidth(10);mPaint.setStyle(Paint.Style.STROKE);canvas.drawBitmap(mFaceBitmap, 0, 0, mPaint);for (int i = 0; i < faceCount; i++){//双眼的中心点PointF midPoint = new PointF();faces[i].getMidPoint(midPoint);//双眼的距离float eyeDistance = faces[i].eyesDistance();//画矩形canvas.drawRect(midPoint.x - eyeDistance, midPoint.y - eyeDistance, midPoint.x + eyeDistance, midPoint.y + eyeDistance, mPaint);}return bitmap;}
}

测试图片face.jpg

运行结果