Android上使调用OpenCV 2.4.10 实现二维码区域定位（Z-xing 码）

Android上使调用OpenCV 2.4.10 实现二维码区域定位（Z-xing 码）

该文章主要用于笔者自己学习中的总结，暂贴出代码部分，待以后有时间再补充算法的详细细节。

Activity class Java 文件

package cn.hjq.android_capture;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.List;

import org.opencv.android.BaseLoaderCallback;
import org.opencv.android.LoaderCallbackInterface;
import org.opencv.android.OpenCVLoader;
import org.opencv.core.*;
import org.opencv.highgui.*;
import org.opencv.imgproc.*;
import org.opencv.utils.Converters;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.hardware.Camera;
import android.hardware.Camera.AutoFocusCallback;
import android.hardware.Camera.Parameters;
import android.hardware.Camera.PictureCallback;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.app.Activity;
import android.content.pm.ActivityInfo;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;
import android.view.View;

public class capture extends Activity {
	private SurfaceView picSV;
	private Camera camera;
	private String strPicPath;
	
	//OpenCV类库加载并初始化成功后的回调函数，在此我们不进行任何操作  
    private BaseLoaderCallback  mLoaderCallback = new BaseLoaderCallback(this) {  
        @Override  
        public void onManagerConnected(int status) {  
            switch (status) {  
                case LoaderCallbackInterface.SUCCESS:{  
                } break;  
                default:{  
                    super.onManagerConnected(status);  
                } break;  
            }  
        }  
    };
	
	@SuppressWarnings("deprecation")
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
		setContentView(R.layout.main);
		picSV = (SurfaceView) findViewById(R.id.picSV);
		picSV.getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);	
		picSV.getHolder().addCallback(new MyCallback());
	}
  
	private class MyCallback implements Callback{
	//我们在SurfaceView创建的时候就要进行打开摄像头、设置预览取景所在的SurfaceView、设置拍照的参数、开启预览取景等操作
		@Override
		public void surfaceCreated(SurfaceHolder holder) {
			try {
				camera = Camera.open();//打开摄像头
				camera.setPreviewDisplay(picSV.getHolder());//设置picSV来进行预览取景
				Parameters params = camera.getParameters();//获取照相机的参数
				params.setPictureSize(800, 480);//设置照片的大小为800*480
				params.setPreviewSize(800, 480);//设置预览取景的大小为800*480
				params.setFlashMode("auto");//开启闪光灯
				params.setJpegQuality(50);//设置图片质量为50       
				camera.setParameters(params);//设置以上参数为照相机的参数
				camera.startPreview();
			} 
			catch (IOException e) {				//开始预览取景，然后我们就可以拍照了
		  		e.printStackTrace();
			}
		}
	  
		@Override
		public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
		}
	
		@Override
		public void surfaceDestroyed(SurfaceHolder holder) {
			//当SurfaceView销毁时，我们进行停止预览、释放摄像机、垃圾回收等工作
			camera.stopPreview();
			camera.release();
			camera = null;
		} 
	}
  
	public void takepic(View v){
		//在我们开始拍照前，实现自动对焦
		camera.autoFocus(new MyAutoFocusCallback());
	}
  
	private class MyAutoFocusCallback implements AutoFocusCallback{
		@Override
		public void onAutoFocus(boolean success, Camera camera) {
			//开始拍照
			camera.takePicture(null, null, null, new MyPictureCallback());
		}
	}
  
	private class MyPictureCallback implements PictureCallback{
		@Override
		public void onPictureTaken(byte[] data, Camera camera) {
			try {
				Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);  
				Matrix matrix = new Matrix();  
				matrix.preRotate(90);  
				bitmap = Bitmap.createBitmap(bitmap ,0,0, bitmap.getWidth(),
											 bitmap.getHeight(),matrix,true);
				strPicPath = 
				  Environment.getExternalStorageDirectory()+"/1Zxing/"+System.currentTimeMillis()+".jpg";
				FileOutputStream fos = new FileOutputStream( strPicPath );
				bitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
				fos.close();
				Handler mHandler = new Handler();
			    mHandler.post(mRunnable);
				camera.startPreview();
			} 
			catch (Exception e) {
				e.printStackTrace();
			}
		} 
	}
	
	public boolean onTouchEvent (MotionEvent event)
    {
        int Action = event.getAction();
        if ( 1 == Action ) {
        	camera.autoFocus(new MyAutoFocusCallback1());
        }
        return true;
    }
	
	private class MyAutoFocusCallback1 implements AutoFocusCallback {
		@Override
		public void onAutoFocus(boolean success, Camera camera) {
		}
	}
	
	@Override  
    public void onResume(){  
        super.onResume();  
        //通过OpenCV引擎服务加载并初始化OpenCV类库，所谓OpenCV引擎服务即是  
        //OpenCV_2.4.3.2_Manager_2.4_*.apk程序包，存在于OpenCV安装包的apk目录中  
        OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_10, this, mLoaderCallback);  
    }

	Runnable mRunnable = new Runnable() {
        public void run() {
        	List<MatOfPoint> contours = new ArrayList<MatOfPoint>();
        	String strMissingTime = null;
        	Mat srcColor = new Mat(), srcColorResize = new Mat();
        	Mat srcGray = new Mat(), srcGrayResize = new Mat(), srcGrayResizeThresh = new Mat();
			srcGray = Highgui.imread(strPicPath, 0);
			srcColor = Highgui.imread(strPicPath, 1);
			Imgproc.resize(srcGray, srcGrayResize, new Size(srcGray.cols()*0.2,srcGray.rows()*0.2));
			Imgproc.resize(srcColor, srcColorResize, new Size(srcGray.cols()*0.2,srcGray.rows()*0.2));
			long start = System.currentTimeMillis();
			//二值化加轮廓寻找
			Imgproc.adaptiveThreshold(srcGrayResize, srcGrayResizeThresh, 255,
									  Imgproc.ADAPTIVE_THRESH_GAUSSIAN_C,
									  Imgproc.THRESH_BINARY, 35, 5);
			Imgproc.findContours(srcGrayResizeThresh, contours, new Mat(),
								 Imgproc.RETR_LIST, Imgproc.CHAIN_APPROX_NONE);
			long end = System.currentTimeMillis();
			strMissingTime = String.valueOf( end - start );
			strMissingTime = strMissingTime + "\r";
			//轮廓绘制
		 	for ( int i = contours.size()-1; i >= 0; i-- )
		 	{
		 		MatOfPoint2f NewMtx = new MatOfPoint2f( contours.get(i).toArray() );
		 		RotatedRect rotRect = Imgproc.minAreaRect( NewMtx );
		 		Point vertices[] = new Point[4];
		 		rotRect.points(vertices);
		 		List<Point> rectArea = new ArrayList<Point>();
		 		for ( int n = 0; n < 4; n ++ )
		 		{
		 			Point temp = new Point();
		 			temp.x = vertices[n].x;
		 			temp.y = vertices[n].y;
		 			rectArea.add(temp);
		 		}
		 		Mat rectMat = Converters.vector_Point_to_Mat(rectArea);
		 		double minRectArea = Imgproc.contourArea( rectMat );
		 		Point center = new Point();
		 		float radius[] = {0};
		 		Imgproc.minEnclosingCircle(NewMtx, center, radius);
		 		if( 
		 			Imgproc.contourArea( contours.get(i)) < 300 ||
		 			Imgproc.contourArea( contours.get(i)) > 3000
		 			|| minRectArea < radius[0]*radius[0]*1.57
		 		) contours.remove(i);
		 	}
		 	Imgproc.drawContours(srcColorResize, contours, -1, new Scalar(255,0,0));
			Highgui.imwrite(Environment.getExternalStorageDirectory()+"/1Zxing/"
							+System.currentTimeMillis()+"contour.jpg", srcColorResize);			
			File file=new File(Environment.getExternalStorageDirectory()+"/1Zxing/","log.txt");  
	        BufferedWriter out = null;  
	        try {
		        out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file, true)));  
		        out.write(strMissingTime); 
		        out.close();
	        }
	        catch (Exception e) {
	        	e.printStackTrace();
	        }			
		}
	};
}

layout.xml 文件

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >
    
    <SurfaceView
        android:id="@+id/picSV"
        android:layout_width="match_parent"
    	android:layout_height="match_parent"
    	>
    </SurfaceView>
    
    <ImageButton
        android:contentDescription="@string/desc"
        android:onClick="takepic"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="right|top"
        android:src="@android:drawable/ic_menu_camera" />
    
</FrameLayout>

string.xml 文件

<resources>
    <string name="app_name">Code</string>
    <string name="desc">Take picture button</string>
</resources>

style.xml 文件（理论上是可以自动生成，若自动生成内容有错，可以参考）

<resources>

    <!--
        Base application theme, dependent on API level. This theme is replaced
        by AppBaseTheme from res/values-vXX/styles.xml on newer devices.
    -->
    <style name="AppBaseTheme" parent="android:Theme.Light">
        <!--
            Theme customizations available in newer API levels can go in
            res/values-vXX/styles.xml, while customizations related to
            backward-compatibility can go here.
        -->
    </style>

    <!-- Application theme. -->
    <style name="AppTheme" parent="AppBaseTheme">
        <!-- All customizations that are NOT specific to a particular API-level can go here. -->
		<item name="android:windowNoTitle">true</item>
		<item name="android:windowFullscreen">true</item>
    </style>
 

</resources>

AndroidManifest.xml 文件

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="cn.hjq.android_capture"
    android:versionCode="1"
    android:versionName="1.0" >
    
	<uses-permission 
	    android:name="android.permission.CAMERA"/>
	<uses-permission 
	    android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity 
            android:name=".capture" >  
            <intent-filter >  
                <action android:name="android.intent.action.MAIN" />  
                <category android:name="android.intent.category.LAUNCHER" />  
            </intent-filter>  
        </activity>
    </application>

</manifest>