在android平台上利用opencv进行图像处理之边沿检测

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由于项目的需要，这几天开始接触opencv，要在android平台上利用opencv进行图像处理。以下是这几天的成果：

运行结果如下：

原始图片：

处理后的图片：

Java代码：

package com.cdq.opencvtest;

import java.io.File;

import org.opencv.android.BaseLoaderCallback;
import org.opencv.android.LoaderCallbackInterface;
import org.opencv.android.OpenCVLoader;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.Size;
import org.opencv.highgui.Highgui;
import org.opencv.imgproc.Imgproc;

import android.os.Bundle;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends Activity
{

	private ImageView iv = null;
	private Button btn1 = null;
	private Button btn2 = null;
	String tag="MainActivity";
	 //OpenCV类库加载并初始化成功后的回调函数
	private BaseLoaderCallback mLoader = new BaseLoaderCallback(this)
	{

		@Override
		public void onManagerConnected(int status)
		{
			switch (status)
			{
			case LoaderCallbackInterface.SUCCESS:
			{
			}break;
			default:
			{
				super.onManagerConnected(status);
			}break;
			}
		}

	};
	@Override
	protected 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 Manager
		OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_9, this,mLoader);
	}
	@Override
	protected void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		iv = (ImageView) findViewById(R.id.iv);
		btn1 = (Button) findViewById(R.id.btn1);
		btn2 = (Button) findViewById(R.id.btn2);
		Bitmap bitmap = BitmapFactory.decodeFile("/sdcard/face8.jpg");
		iv.setImageBitmap(bitmap);
		btn1.setOnClickListener(new OnClickListener()
		{
			@Override
			public void onClick(View arg0)
			{
				Mat img = Highgui.imread("/sdcard/face8.jpg", 0);
				Size dSize = new Size((double) img.width(), (double) img.height());
				Mat img2 = new Mat(dSize, CvType.CV_8SC1);
				Mat img3 = new Mat();
				img.convertTo(img2, CvType.CV_8SC1);
				Imgproc.Canny(img, img3, 123, 250);
				boolean flag = Highgui.imwrite("/sdcard/new.jpg", img3);
				Log.i(tag, "onClick");
				if (flag)
				{
					Log.i(tag, "flag");
					File file = new File("/sdcard/new.jpg");
					if (file.exists())
					{
						Bitmap bitmap2 = BitmapFactory.decodeFile("/sdcard/new.jpg");
						iv.setImageBitmap(bitmap2);
					}
				}
				else
				{
					Toast.makeText(getApplicationContext(), "图片写入失败",
							Toast.LENGTH_SHORT).show();
				}
				
			}
		});
		btn2.setOnClickListener(new OnClickListener()
		{
			
			@Override
			public void onClick(View arg0)
			{
				Bitmap bitmap = BitmapFactory.decodeFile("/sdcard/face8.jpg");
				iv.setImageBitmap(bitmap);
			}
		});
	}
	@Override
	public boolean onCreateOptionsMenu(Menu menu)
	{
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}
}

AndroidMenifest.xml文件：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.cdq.opencvtest"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="14" />
	<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
	<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.cdq.opencvtest.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

布局文件：

<LinearLayout 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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <TableLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
        android:layout_weight="1"
        >

        <ImageView
            android:id="@+id/iv"
            android:layout_width="fill_parent"
            android:layout_height="0dp"
            android:layout_weight="9" />

        <TableRow
            android:id="@+id/tableRow1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <Button
                android:id="@+id/btn1"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:text="处理"
                android:layout_weight="1"/>

            <Button
                android:id="@+id/btn2"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:text="恢复" 
                android:layout_weight="1"/>
        </TableRow>

    </TableLayout>

</LinearLayout>

实践过程中，一直有个问题纠结了我很久—— java.lang.UnsatisfiedLinkError: Native method not found: org.opencv.highgui.Highgui.imread_0:(Ljava/lang/String;I)。在网上看了很多资料后，才明白其实是程序没有加载opencv类库。于是我加入了以下代码后，问题得到了解决：

//OpenCV类库加载并初始化成功后的回调函数
	private BaseLoaderCallback mLoader = new BaseLoaderCallback(this)
	{

		@Override
		public void onManagerConnected(int status)
		{
			switch (status)
			{
			case LoaderCallbackInterface.SUCCESS:
			{
			}break;
			default:
			{
				super.onManagerConnected(status);
			}break;
			}
		}

	};
	@Override
	protected 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 Manager
		OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_9, this,mLoader);
	}