给你个小例子吧：
package colorconvert;

import java.awt.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.color.ColorSpace;
import java.awt.image.*;

public class ColorConvertFrm extends JFrame {

ColorConvert panel;
Container contentPane;
BorderLayout borderLayout1 = new BorderLayout();
public ColorConvertFrm() {
enableEvents(AWTEvent.WINDOW_EVENT_MASK);
try {
jbInit();
}
catch(Exception e) {
e.printStackTrace();
}
}
private void jbInit() throws Exception {
panel = new ColorConvert();
contentPane = getContentPane();
contentPane.add(panel);
this.setSize(new Dimension(panel.w*2, panel.h + 25));
this.setTitle("应用Java 2D API进行图像颜色空间转换处理");
}
protected void processWindowEvent(WindowEvent e) {
super.processWindowEvent(e);
if (e.getID() == WindowEvent.WINDOW_CLOSING) {
System.exit(0);
}
}


public class ColorConvert extends JPanel {
private Image img;
public int w;
public int h;
public ColorConvert(){
img = getToolkit().getImage(
ClassLoader.getSystemResource("Image.gif"));
MediaTracker mt = new MediaTracker(this); // 加载图片
mt.addImage(img,0);
try{ // 判断图片是否完全加载
mt.waitForAll();
}
catch(Exception err){
err.printStackTrace();
}
w = img.getWidth(this);
h = img.getHeight(this);
this.setSize(w*2,h);
}
public void paintComponent(Graphics g){
super.paintComponent(g);
ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
BufferedImage bi = new BufferedImage(w,h,BufferedImage.TYPE_INT_RGB);
Graphics2D big = bi.createGraphics();
big.drawImage(img,0,0,this);
BufferedImage bimg = new BufferedImage(w,h, BufferedImage.TYPE_INT_RGB);
ColorConvertOp cop = new ColorConvertOp(cs,null); // 创建灰化颜色转换器
cop.filter(bi,bimg);
Graphics2D g2d = (Graphics2D)g;
g2d.drawImage(img, 0, 0, w, h, null);
g2d.drawImage(bimg, w, 0, w, h, null);
}
}
public static void main(String[] args) {
ColorConvertFrm colorConvertFrm = new ColorConvertFrm();
colorConvertFrm.show();
}
}