Java实现提取图片边缘的示例代码

package qrcodeServer;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import javax.imageio.ImageIO;
public class ServerMain {
	static final String rootpath="E:\\desktop\\";
	static final int Y=30;
	static boolean isboard(BufferedImage ash,int now_x,int now_y,int w,int h,int[][] kernel1,int[][] kernel2)
	{
		int tmp=kernel1.length/2;
		int x=now_x-tmp,y=now_y-tmp;
		int ken1=0,ken2=0;
		for(int i=x;i<x+kernel1.length;i++)
		{
			for(int j=y;j<y+kernel1.length;j++)
			{
				if(i<0||j<0||i>=w||j>=h)
				{
					return true;
				}
				ken1+=RGBtoAsh(ash.getRGB(i, j))*kernel1[i-x][j-y];
				ken2+=RGBtoAsh(ash.getRGB(i, j))*kernel2[i-x][j-y];
			}
		}
		ken1=ken1<0?-ken1:ken1;
		ken2=ken2<0?-ken2:ken2;
		return (ken1+ken2)/2>Y;
	}
	public static int RGBtoAsh(int rgb)
	{
		int tmp=0;
		for(int i=0;i<3;i++)
		{
			tmp+=(rgb>>(i*8))&0xFF;
		}
		return tmp/3;
	}
	public static int AshtoRGB(int ash)
	{
		int tmp=0xFF000000;
		for(int i=0;i<3;i++)
		{
			tmp|=(ash<<(i*8));
		}
		return tmp;
	}
	public static void main(String[] args) {
		try {
			BufferedImage bimg=ImageIO.read(new File(rootpath+"1.jpg"));
			int w=bimg.getWidth(),h=bimg.getHeight();
			BufferedImage bimgot=new BufferedImage(w, h, Image.SCALE_DEFAULT);
			BufferedImage tmp=new BufferedImage(w, h, Image.SCALE_DEFAULT);
			int kernel1[][]= {{1,1,1,1},
					{0,0,0,0},
					{0,0,0,0},
					{-1,-1,-1,-1}};
			int kernel2[][]= {{-1,0,0,1},
					{-1,0,0,1},
					{-1,0,0,1},
					{-1,0,0,1}
					};
			for(int i=0;i<bimg.getWidth();i++)
				for(int j=0;j<bimg.getHeight();j++)
				{
					if(isboard(bimg, i, j, w, h, kernel1,kernel2))
						bimgot.setRGB(i,j,0);
					else
						bimgot.setRGB(i,j,0xFFFFFFFF);
				}
			ImageIO.write(bimgot, "jpg",new File(rootpath+"out.jpg"));
		} catch (FileNotFoundException e) {
			// TODO 自动生成的 catch 块
			e.printStackTrace();
		} catch (IOException e) {
			// TODO 自动生成的 catch 块
			e.printStackTrace();
		}
	}
}