Wednesday, October 17, 2012

Face Detection Example in Android

This example will help you to create face detection application.
Algorithm:
1.) Create a new project by File-> New -> Android Project name it FaceDetectionExample.
2.) Write following into res/values/strings.xml:
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<resources>
 
    <string name="app_name">FaceDetectionExample</string>
    <string name="hello_world">Hello world!</string>
    <string name="menu_settings">Settings</string>
    <string name="title_activity_face_detection_example">FaceDetectionExample</string>
    <string name="app_info">Click on the \'Take Picture\' to take a picture using Camera and detect the face(s) in the picture taken.</string>
    <string name="take_picture">Take Picture</string>
    <string name="detect_face">Detect Face</string>
</resources>
3.) Create and write following into res/layout/detectlayout.xml:
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<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent">
         
        <ImageView
                android:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:id="@+id/image_view"
                android:layout_weight="1.0"/>
                 
        <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/detect_face"
                android:text="@string/detect_face"
                android:layout_gravity="center_horizontal"/>
         
</LinearLayout>
4.) Write following into main.xml:
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<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:padding="10dip">
 
        <TextView 
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/app_info"
        android:gravity="center_horizontal"
        android:layout_weight="1.0"/>
         
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/take_picture"
        android:layout_margin="5dip"
        android:text="@string/take_picture"
        android:layout_gravity="center_horizontal"/>
</LinearLayout>
5.) Write following into AndroidManifest.xml:
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<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.facedetectionexample"
    android:versionCode="1"
    android:versionName="1.0" >
 
    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="15" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".FaceDetectionExample"
            android:label="@string/title_activity_face_detection_example" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
 
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
 
</manifest>
6.) Run for output.
Steps:
1.) Create a project named FaceDetectionExample and set the information as stated in the image.
Build Target: Android 4.0
Application Name: FaceDetectionExample
Package Name: com. example. FaceDetectionExample
Activity Name: FaceDetectionExample
Min SDK Version: 2.2
2.) Open FaceDetectionExample.java file and write following code there:
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package com.example.facedetectionexample;
 
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
 
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.Bitmap.Config;
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.os.Environment;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
 
public class FaceDetectionExample extends Activity {
    private static final int TAKE_PICTURE_CODE = 100;
    private static final int MAX_FACES = 5;
     
    private Bitmap cameraBitmap = null;
     
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
     
    ((Button)findViewById(R.id.take_picture)).setOnClickListener(btnClick);
}
 
@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
     
            if(TAKE_PICTURE_CODE == requestCode){
                    processCameraImage(data);
            }
    }
 
private void openCamera(){
    Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
     
    startActivityForResult(intent, TAKE_PICTURE_CODE);
}
 
private void processCameraImage(Intent intent){
    setContentView(R.layout.detectlayout);
     
    ((Button)findViewById(R.id.detect_face)).setOnClickListener(btnClick);
     
    ImageView imageView = (ImageView)findViewById(R.id.image_view);
     
    cameraBitmap = (Bitmap)intent.getExtras().get("data");
     
    imageView.setImageBitmap(cameraBitmap);
}
 
private void detectFaces(){
    if(null != cameraBitmap){
            int width = cameraBitmap.getWidth();
            int height = cameraBitmap.getHeight();
             
            FaceDetector detector = new FaceDetector(width, height,FaceDetectionExample.MAX_FACES);
            Face[] faces = new Face[FaceDetectionExample.MAX_FACES];
             
            Bitmap bitmap565 = Bitmap.createBitmap(width, height, Config.RGB_565);
            Paint ditherPaint = new Paint();
            Paint drawPaint = new Paint();
             
            ditherPaint.setDither(true);
            drawPaint.setColor(Color.RED);
            drawPaint.setStyle(Paint.Style.STROKE);
            drawPaint.setStrokeWidth(2);
             
            Canvas canvas = new Canvas();
            canvas.setBitmap(bitmap565);
            canvas.drawBitmap(cameraBitmap, 0, 0, ditherPaint);
             
            int facesFound = detector.findFaces(bitmap565, faces);
            PointF midPoint = new PointF();
            float eyeDistance = 0.0f;
            float confidence = 0.0f;
             
            Log.i("FaceDetector", "Number of faces found: " + facesFound);
             
            if(facesFound > 0)
            {
                    for(int index=0; index<facesFound; ++index){
                            faces[index].getMidPoint(midPoint);
                            eyeDistance = faces[index].eyesDistance();
                            confidence = faces[index].confidence();
                             
                            Log.i("FaceDetector",
                                            "Confidence: " + confidence +
                                            ", Eye distance: " + eyeDistance +
                                            ", Mid Point: (" + midPoint.x + ", " + midPoint.y + ")");
                             
                            canvas.drawRect((int)midPoint.x - eyeDistance ,
                                                            (int)midPoint.y - eyeDistance ,
                                                            (int)midPoint.x + eyeDistance,
                                                            (int)midPoint.y + eyeDistance, drawPaint);
                    }
            }
             
            String filepath = Environment.getExternalStorageDirectory() + "/facedetect" + System.currentTimeMillis() + ".jpg";
             
                    try {
                            FileOutputStream fos = new FileOutputStream(filepath);
                             
                            bitmap565.compress(CompressFormat.JPEG, 90, fos);
                             
                            fos.flush();
                            fos.close();
                    } catch (FileNotFoundException e) {
                            e.printStackTrace();
                    } catch (IOException e) {
                            e.printStackTrace();
                    }
                     
                    ImageView imageView = (ImageView)findViewById(R.id.image_view);
                     
                    imageView.setImageBitmap(bitmap565);
    }
}
 
    private View.OnClickListener btnClick = new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                    switch(v.getId()){
                            case R.id.take_picture:         openCamera();   break;
                            case R.id.detect_face:          detectFaces();  break; 
                    }
            }
    };
}
3.) Compile and build the project.
Note:- For better results check on device.
Output
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