Android自带的人脸识别

1. Android自带的人脸识别
Android自带的人脸识别只能识别出人脸在画面中的位置，中点，眼间距，角度等基本特性，提供给拍照性质的应用使用。从基本功能中不能得出明显的特征数据
2. 底层库支持
external/neven/*
3. 接口
frameworks/base/media/java/android/media/FaceDetector.java
4. Android源码参考
packages/apps/Gallery/src/com/android/camera/*
5. 关键代码分析
package com.android.mydetect;

import android.app.Activity;
import android.widget.TextView;
import android.os.Bundle;
import android.media.FaceDetector; // 人脸识别接口
import android.widget.ImageView;
import android.graphics.BitmapFactory;
import android.graphics.Bitmap;
import android.graphics.PointF;
import android.graphics.Matrix;
import android.util.Log;
import android.graphics.Canvas;
import android.graphics.Paint;

public class MyDetectActivity extends Activity {
private ImageView mImageView; // 图片显示控件
private Bitmap mBitmap;
private float mScale = 1F;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mImageView = (ImageView) this.findViewById(R.id.image);
detect(); // 识别函数
}

private void handleFace(FaceDetector.Face f) { // 在图片上对每张脸进行处理
PointF midPoint = new PointF();
int r = ((int) (f.eyesDistance() * mScale * 1.5)); // 取眼睛间距离
f.getMidPoint(midPoint); // 取脸的中点
midPoint.x *= mScale;
midPoint.y *= mScale;
Canvas c = new Canvas(mBitmap);
Paint p = new Paint();
p.setAntiAlias(true);
p.setAlpha(0x80);
c.drawCircle(midPoint.x, midPoint.y, r, p) // 用半透明标出人脸区域;
mImageView.setImageBitmap(mBitmap); // 显示图片
}

private void detect() {
Matrix matrix = new Matrix();
FaceDetector.Face[] mFaces = new FaceDetector.Face[3]; // 定义最多识别三张脸
int mNumFaces = 0;

mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.baby); // 取原始图
if (mBitmap == null) {
return;
}
if (mBitmap.getWidth() > 256) {
mScale = 256.0F / mBitmap.getWidth();
}
matrix.setScale(mScale, mScale);
Bitmap faceBitmap = Bitmap.createBitmap(mBitmap, 0, 0, mBitmap
.getWidth(), mBitmap.getHeight(), matrix, true); // 生成缩放后的新图

mScale = 1.0F / mScale;
if (faceBitmap != null) {
FaceDetector detector = new FaceDetector(faceBitmap.getWidth(),
faceBitmap.getHeight(), mFaces.length); // 创建识别器
mNumFaces = detector.findFaces(faceBitmap, mFaces); // 识别
if (mNumFaces > 0) {
for (int i = 0; i < mNumFaces; i++) {
handleFace(mFaces[i]); // 调用函数对人脸画面进行处理
}
}
}
}
}
6. 完整例程下载
http://download.csdn.net/source/2612476