Android平台上利用opencv进行图像的边沿检测

在Android2.3.1模拟器上跑了，如下：

 

 

代码如下：

 

package cn.netjava.opencv;

import java.io.File;

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.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

public class TestOpencv extends Activity {

    private Button deal_button, recall_button;
    private ImageView imageview;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        double scale = 0.1;
        imageview =  (ImageView)this.findViewById(R.id.imageView1);
        Bitmap bm1=BitmapFactory.decodeFile("/sdcard/girl.jpg");
        imageview.setImageBitmap(bm1);
        Mat img = Highgui.imread("/sdcard/girl.jpg",0);

        Size dsize = new Size(img.width()*scale,img.height()*scale);
        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);
        if(flag)
        {
            File f = new File("/sdcard/new.jpg");
            if(f.exists())
            {
                Bitmap bm=BitmapFactory.decodeFile("/sdcard/new.jpg");
                imageview.setImageBitmap(bm);
            }
        }//end if
        else{
        Toast.makeText(TestOpencv.this, "===========图片写入失败！============！！", 3).show();
        }
    }
}

package cn.netjava.opencv;

import java.io.File;

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.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

public class TestOpencv extends Activity {

	private Button deal_button, recall_button;
	private ImageView imageview;

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		double scale = 0.1;
		imageview =  (ImageView)this.findViewById(R.id.imageView1);
		Bitmap bm1=BitmapFactory.decodeFile("/sdcard/girl.jpg");
		imageview.setImageBitmap(bm1);
		Mat img = Highgui.imread("/sdcard/girl.jpg",0);
		
		Size dsize = new Size(img.width()*scale,img.height()*scale);
		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);
		if(flag)
		{
			File f = new File("/sdcard/new.jpg");
			if(f.exists())
			{
				Bitmap bm=BitmapFactory.decodeFile("/sdcard/new.jpg");
				imageview.setImageBitmap(bm);
			}
		}//end if
		else{
		Toast.makeText(TestOpencv.this, "===========图片写入失败！============！！", 3).show();
		}
	}
}

 

 

但自己在实践过程中，一个小问题着实费了我一番功夫。

将进行转化的矩阵写到sdcard中，总是写不进去。

弄了很多，多亏一学姐指点，程序对sdcard进行操作时，要在XML文件中进行权限控制。

 

<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

 

 在AndroidManifest.xml中加入上面两行代码一切OK啦~