直方图均衡化的java代码

自我感觉直方图均衡化作用并不是很大，有的时候甚至会适得其反。它的核心思想就是让图像暗的地方变亮，亮的地方变暗。问题是，如果图像原本的亮暗程度就非常符合人眼的观察结果，那么直方图均衡化之后的图像就变的很糟。所以该方法要依据图像数据的特点而定。先看一下效果比较好的案例：
彩色的lena图像：lena_color.jpg




将彩色lena变为灰度lena：




对灰度lena进行直方图均衡化，结果如下，可以看出，图像整体变亮，暗处的细节得到了突出：





但是对于某些图像，尤其是亮背景的图像，本来前景和背景有很好的区分，但是直方图均衡化之后，亮的背景变暗，图像灰度成平稳过渡状态，反而不利于图像信息的展示，如下图：girl.jpg:





直方图均衡化后，结果如下，可以看到，结果并不理想：

package p01;

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.swing.*;

public class hist extends Frame{
	Image im, tmp;
	int iw, ih;
	int[] pixels;
	boolean flag_load = false;
	boolean flag_grey = false;
	//hist的构造方法
	public hist(){
		this.setTitle("直方图均衡化");
		Panel pdown;
		Button load, grey, hist, run, save, quit;
		//添加窗口监听事件
		addWindowListener(new WindowAdapter(){
			public void windowClosing(WindowEvent e){
				System.exit(0);
			}
		}
		);
	    pdown = new Panel();
	    pdown.setBackground(Color.LIGHT_GRAY);
	    //按钮名称
	    load = new Button("装载图像");
	    grey = new Button("灰度图像");
	    hist = new Button("直方图");
	    run = new Button("均衡化");
	    save = new Button("保存");
	    quit = new Button("退出");
	    
	    this.add(pdown, BorderLayout.SOUTH);
	    //增加按钮
	    pdown.add(load);
	    pdown.add(grey);
	    pdown.add(hist);
	    pdown.add(run);
	    pdown.add(save);
	    pdown.add(quit);
	  //按钮的动作程序  装载图像
    	load.addActionListener(new ActionListener(){    
    		public void actionPerformed(ActionEvent e){
    			try {
					jLoad_ActionPerformed(e);
				} catch (IOException e1) {	
					e1.printStackTrace();
				}
    		}
    	});
    	//按钮的动作程序  灰度化
    	grey.addActionListener(new ActionListener(){    
    		public void actionPerformed(ActionEvent e){
    			try {
					jGrey_ActionPerformed(e);
				} catch (IOException e1) {
					e1.printStackTrace();
				}
    		}
    	});
    	//按钮的动作程序  直方图
    	hist.addActionListener(new ActionListener(){    
    		public void actionPerformed(ActionEvent e){
    			jHist_ActionPerformed(e);
    		}
    	});
    	//按钮的动作程序 直方图均衡化
    	run.addActionListener(new ActionListener(){    
    		public void actionPerformed(ActionEvent e){
    			jRun_ActionPerformed(e);
    		}
    	});
    	//按钮的动作程序 保存
    	save.addActionListener(new ActionListener(){    
    		public void actionPerformed(ActionEvent e){
    			try {
					jSave_ActionPerformed(e);
				} catch (IOException e1) {
					e1.printStackTrace();
				}
    		}
    	});
    	//按钮的动作程序  退出
    	quit.addActionListener(new ActionListener(){    
    		public void actionPerformed(ActionEvent e){
    			jQuit_ActionPerformed(e);
    		}
    	});    
	}
	//按钮动作的实现  加载图像
    public void jLoad_ActionPerformed(ActionEvent e) throws IOException{    
    	File inputFile = new File("E:\\f2\\sc\\source.jpg");
        BufferedImage input = ImageIO.read(inputFile);
        
        im = input;
		tmp = input;
        flag_load = true;
        repaint();
	}
    //按钮动作的实现  灰度化
    public void jGrey_ActionPerformed(ActionEvent e) throws IOException{
		if(flag_load){
			File inputFile = new File("E:\\f2\\sc\\source.jpg");
  			BufferedImage input = ImageIO.read(inputFile);
  			iw = input.getWidth(this);
  		    ih = input.getHeight(this);
  		    pixels = new int[iw*ih];
  		    
			BufferedImage grayImage = new BufferedImage(iw, ih, 
  					BufferedImage.TYPE_BYTE_GRAY);
			for(int i=0; i<iw; i++){
  				for(int j=0; j<ih; j++){
  					int rgb = input.getRGB(i, j);  
  					int grey = (int) (0.3*((rgb&0xff0000 )>>16)+0.59*((rgb&0xff00 )>>8)+0.11*((rgb&0xff))); 
  					rgb = 255<<24|grey<<16|grey<<8|grey;
  					grayImage.setRGB(i, j, rgb);
  				}
  			}
  			tmp = grayImage;
  			try{
    			PixelGrabber pg = new PixelGrabber(tmp,0,0,iw,ih,pixels,0,iw);
    			pg.grabPixels();
    		}catch(InterruptedException e3){
    			e3.printStackTrace();
    	}
  			flag_grey = true;
  			repaint();
			} else{
				JOptionPane.showMessageDialog(null, "先点击“装载图像”，3Q！","提示：",
						JOptionPane.WARNING_MESSAGE);
			}
	}
    //按钮动作的实现 直方图显示 调用histshow这个类进行操作
    public void jHist_ActionPerformed(ActionEvent e){
    	histshow h = new histshow();
    	h.getData(pixels, iw, ih);
    	h.setSize(480,350);
    	h.setVisible(true);
    	
    }
  //按钮动作的实现 直方图均衡化 
    public void jRun_ActionPerformed(ActionEvent e){
    	if(flag_load&&flag_grey){
    		try{
    			PixelGrabber pg = new PixelGrabber(tmp,0,0,iw,ih,pixels,0,iw);
    			pg.grabPixels();
    		}catch(InterruptedException e3){
    			e3.printStackTrace();
    	}
    	BufferedImage greyImage = new BufferedImage(iw, ih, 
					BufferedImage.TYPE_BYTE_GRAY);
    	//获取图像的直方图
    	int[] histogram = new int[256];
    	for(int i=0; i<ih-1; i++){
    		for(int j=0; j<iw-1; j++){
    			int grey = pixels[i*iw+j]&0xff;
    			histogram[grey]++;
    		}
    	}
    	//直方图均衡化
    	double a = (double)255/(iw*ih);
    	double[] c = new double [256];
    	c[0] = (a*histogram[0]);
    	for(int i=1; i<256; i++){
    		c[i] = c[i-1]+(int)(a*histogram[i]);
    	}
    	for(int i=0; i<ih; i++){
    		for(int j=0; j<iw; j++){
    			int grey = pixels[i*iw+j]&0x0000ff;
    			int hist = (int)(c[grey]);
    			pixels[i*iw+j] = 255<<24|hist<<16|hist<<8|hist;
    			greyImage.setRGB(j, i, pixels[i*iw+j]);
    		}
    	}
    	tmp = greyImage;
  		flag_load = true;
  		repaint();
    	}else{
			JOptionPane.showMessageDialog(null, "先点击“装载图像”，3Q！","提示：",
					JOptionPane.WARNING_MESSAGE);
		}
    }

  //按钮动作的实现保存 
  	public void jSave_ActionPerformed(ActionEvent e) throws IOException{    
        if(flag_load){
        	
    		BufferedImage bi = new BufferedImage(tmp.getWidth(null),tmp.getHeight(null), 
    				BufferedImage.TYPE_INT_RGB);
            Graphics g = bi.getGraphics();
            g.drawImage(tmp,0, 0,null);
            g.dispose();
    		
  		    File save_path=new File("E:\\f2\\sc\\save_t01.jpg");
            ImageIO.write(bi, "JPG", save_path);
  	}else{
  		JOptionPane.showMessageDialog(null, "先点击“装载图像”，3Q！","提示：",
  				JOptionPane.WARNING_MESSAGE);
  		}
  	}
  //按钮动作的实现  退出
  	public void jQuit_ActionPerformed(ActionEvent e){
  		System.exit(0);
  	}
    //绘图函数
  	public void paint(Graphics g){
  		//if(flag_Load){
  			g.drawImage(tmp,50,50,this);
  		//}else{}
  	}
  	
	public static void main(String[] args) {
		hist ti = new hist();
		ti.setSize(900,860);
		ti.setVisible(true);
	}
}

//上面的代码应用到了histshow类，如下：

package p01;

import java.awt.*;
import java.awt.event.*;
import java.awt.Window;

public class histshow extends Frame{
	int data[];
	int histogram[] = new int[256];
	
	public histshow(){
		this.setTitle("图像的灰度直方图");
		Panel pdown;
		Button quit; 
		pdown = new Panel();
		quit = new Button("关闭窗口");
		this.add(pdown, BorderLayout.SOUTH); 
		pdown.add(quit);
		quit.addActionListener(new ActionListener(){
			public void actionPerformed(ActionEvent e){
				jQuit_ActionPerformed(e);
			}
		});
		// 添加窗口监听事件
		addWindowListener(new WindowAdapter(){
			public void windowClosing(WindowEvent e){
				histshow.this.dispose();
			}
		});
	}
	public void jQuit_ActionPerformed(ActionEvent e){
		this.setVisible(false);
	}
	public void getData(int[] data, int iw, int ih){
		this.data = data;
		for (int i = 0; i < iw * ih; i++){
			int grey = data[i] & 0xff;
			histogram[grey]++;
		}
		
		// 找出最大的数,进行标准化.
		int temp = histogram[0];
		for (int i = 0; i < 256; i++){
			if (temp <= histogram[i]){
			temp = histogram[i];
			//System.out.println(temp);
			}
		}
		for (int i = 0; i < 256; i++){
			histogram[i] = histogram[i] * 200 / temp;
			//System.out.println(temp);
		}
	}
	//画出直方图
	public void paint(Graphics g){
		// 画出水平和垂直的轴
		g.drawLine(100, 250, 356, 250);
		g.drawLine(100, 50, 100, 250);
		// 画出横轴坐标
		g.drawString("0", 98, 263);
		g.drawString("50", 145, 263);
		g.drawString("100", 193, 263);
		g.drawString("150", 243, 263);
		g.drawString("200", 293, 263);
		g.drawString("250", 343, 263);
		// 画出纵轴坐标
		g.drawString("0.5", 83, 145);
		g.drawString("1", 90, 60);
		// 画出图像的直方图
		for (int i = 0; i < 256; i++){
			g.drawLine(100 + i, 250, 100 + i, 250 - histogram[i]);
		}
		g.drawString("该图像的灰度直方图如上所示.", 160, 280);
	}
}

评论

1 楼 探花郎 2013-07-22  

最近在做数字图像处理的大作业，需要做出直方图的均衡化和规定化。在你程序的基础上怎么做菜能实现直方图的规定化。望您不吝赐教。