根據文檔描述，輸入圖片必須為Bitmap RGB565格式。
Android人臉的檢測方法是用雙眼來檢測人臉的位置，也就是說無法檢測到嘴、側臉等，雙眼必須同時可見，並且眼鏡會影響檢測的效果。
實際上，FaceDetector檢測到的並不是人的全臉，而只是雙眼。
實際測試中，發現圖片太小的話檢測不到人臉，試驗中使用小於100x100的圖片檢測不到人臉，但是由於Android內存有限，圖片太大的話，會出現無法加載圖片的異常。
檢測到的人臉存放到FaceDetector.Face類中，該類無法再擴展。從該類可以獲取到人眼的中心位置和雙眼之間的具體。
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);
}
}
}
}
