Android人脸检测类FaceDetector

根据文档描述，输入图片必须为Bitmap RGB565格式。

 

人脸的检测方法是用双眼来检测人脸的位置，也就是说无法检测到嘴、侧脸等，双眼必须同时可见，并且眼镜会影响检测的效果。

 

实际上，FaceDetector检测到的并不是人的全脸，而只是双眼。

 

实际测试中，发现图片太小的话检测不到人脸，试验中使用小于100x100的图片检测不到人脸，但是由于Android内存有限，图片太大的话，会出现无法加载图片的异常。

 

检测到的人脸存放到FaceDetector.Face类中，该类无法再扩展。从该类可以获取到人眼的中心位置和双眼之间的具体。

package name.feisky.face;
 
import android.app.Activity;
import android.content.Context;
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.media.FaceDetector.Face;
import android.os.Bundle;
import android.view.View;
 
public class AndroidFaceDetector extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new myView(this));
    }
 
    private class myView extends View{
 
        private int imageWidth, imageHeight;
        private int numberOfFace = 5;
        private FaceDetector myFaceDetect;
        private FaceDetector.Face[] myFace;
        float myEyesDistance;
        int numberOfFaceDetected;
 
        Bitmap myBitmap;
 
        public myView(Context context) {
            super(context);
            BitmapFactory.Options BitmapFactoryOptionsbfo = new BitmapFactory.Options();
            BitmapFactoryOptionsbfo.inPreferredConfig = Bitmap.Config.RGB_565;
            myBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.pp, BitmapFactoryOptionsbfo);
            imageWidth = myBitmap.getWidth();
            imageHeight = myBitmap.getHeight();
            myFace = new FaceDetector.Face[numberOfFace];
            myFaceDetect = new FaceDetector(imageWidth, imageHeight, numberOfFace);
            numberOfFaceDetected = myFaceDetect.findFaces(myBitmap, myFace);
        }
 
        protected void onDraw(Canvas canvas) {
            // TODO Auto-generated method stub
 
            canvas.drawBitmap(myBitmap, 0, 0, null);
 
            Paint myPaint = new Paint();
            myPaint.setColor(Color.GREEN);
            myPaint.setStyle(Paint.Style.STROKE);
            myPaint.setStrokeWidth(3);
 
            for(int i=0; i < numberOfFaceDetected; i++)
            {
                Face face = myFace[i];
                PointF myMidPoint = new PointF();
                face.getMidPoint(myMidPoint);
                myEyesDistance = face.eyesDistance();
                canvas.drawRect(
                        (int)(myMidPoint.x - myEyesDistance),
                        (int)(myMidPoint.y - myEyesDistance),
                        (int)(myMidPoint.x + myEyesDistance),
                        (int)(myMidPoint.y + myEyesDistance),
                        myPaint);
            }
        }
    }
}