图像处理学习笔记（8）—— 图像灰度化与二值化
1 灰度化
- 平均值法 ：
（R + G + B）/ 3 - 最大最小值法 ：
(Max(R,G,B) + Min(R,G,B)) / 2 - 权重法：
0.299 * R + 0.587 * G + 0.144 * B
- 基于平均值
- 经验值 127
GrayFilter
package demo2.gray;
import demo2.utils.AbstractImageOptionFilter;
import java.awt.image.BufferedImage;
public class GrayFilter extends AbstractImageOptionFilter {public final static int MEANS_RGB = 1;
public final static int MIN_MAX_RGB = 2;
public final static int WEIGHT_RGB = 3;
public final static double MEANS_WEIGHT = 1.0 / 3.0;
private int method;
public GrayFilter() {
method = MEANS_RGB;
}public int getMethod() {
return method;
}public void setMethod(int method) {
this.method = method;
}@Override
public BufferedImage process(BufferedImage src) {
int width = src.getWidth();
int height = src.getHeight();
int[] pixels = new int[width * height];
getRGB(src, 0, 0, width, height, pixels);
BufferedImage dest = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
int[] output = new int[width * height];
int index = 0;
int r = 0, g = 0, b = 0, gray = 0;
for (int row = 0;
row < height;
row++) {
for (int col = 0;
col < width;
col++) {
index = row * width + col;
r = (pixels[index] >> 16) & 0xff;
g = (pixels[index] >> 8) & 0xff;
b = pixels[index] & 0xff;
if (method == MEANS_RGB) {
gray = (int) ((r + g + b) * MEANS_WEIGHT);
} else if (method == MIN_MAX_RGB) {
int max = Math.max(Math.max(r, g), b);
int min = Math.min(Math.min(r, g), b);
gray = (int) ((max + min) / 2.0);
} else if (method == MIN_MAX_RGB) {
gray = (int) (0.299 * r + 0.587 * g + 0.114 * b);
}
output[index] = (0xff << 24) | ((gray & 0xff) << 16) | ((gray & 0xff) << 8) | (gray & 0xff);
}
}setRGB(dest, 0, 0, width, height, output);
return dest;
}}ImagePanel
package demo2.gray;
import demo2.contrast.ContrastAdjust;
import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
public class ImagePanel extends JComponent implements ActionListener {private BufferedImage image;
private BufferedImage resultImage;
private JButton processBtn;
public ImagePanel(BufferedImage image) {
this.image = image;
}public JButton getButton() {
processBtn = new JButton("按钮");
processBtn.addActionListener(this);
return processBtn;
}@Override
protected void paintComponent(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
if (null != image) {
g2d.drawImage(image, 0, 0, image.getWidth(), image.getHeight(), null);
}if(resultImage != null) {
g2d.drawImage(resultImage, image.getWidth() + 10, 0, resultImage.getWidth(), resultImage.getHeight(), null);
}}public void process() {
GrayFilter filter = new GrayFilter();
resultImage = filter.process(this.image);
}@Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == processBtn) {
this.process();
this.repaint();
}
}public static void main(String[] args) {
File file = new File("resource/color.png");
try {
BufferedImage image = ImageIO.read(file);
ImagePanel imp = new ImagePanel(image);
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(imp, BorderLayout.CENTER);
frame.getContentPane().add(imp.getButton(), BorderLayout.SOUTH);
frame.setSize(600, 600);
frame.setTitle("图像显示测试");
frame.setVisible(true);
} catch (IOException e) {
e.printStackTrace();
}}}【图像处理学习笔记（8）—— 图像灰度化与二值化】
文章图片
4 二值化测试
BinaryFilter
package demo2.gray;
import java.awt.*;
import java.awt.image.BufferedImage;
public class BinaryFilter extends GrayFilter {@Override
public BufferedImage process(BufferedImage src) {
BufferedImage grayImage = super.process(src);
int width = grayImage.getWidth();
int height = grayImage.getHeight();
int[] pixels = new int[width * height];
getRGB(grayImage, 0, 0, width, height, pixels);
BufferedImage dest = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
int[] out = new int[width * height];
int means = 0;
long sum = 0;
int index = 0;
int r = 0;
for (int row = 0;
row < height;
row++) {
for (int col = 0;
col < width;
col++) {
index = row * width + col;
r = (pixels[index] >> 16) & 0xff;
sum += r;
}
}means = (int) (sum / pixels.length);
for (int row = 0;
row < height;
row++) {
for (int col = 0;
col < width;
col++) {
index = row * width + col;
r = (pixels[index] >> 16) & 0xff;
if (r >= means) {
out[index] = Color.WHITE.getRGB();
} else {
out[index] = Color.BLACK.getRGB();
}
}
}setRGB(dest, 0, 0, width, height, out);
return dest;
}
}ImagePanel
package demo2.gray;
import demo2.contrast.ContrastAdjust;
import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
public class ImagePanel extends JComponent implements ActionListener {private BufferedImage image;
private BufferedImage resultImage;
private JButton processBtn;
public ImagePanel(BufferedImage image) {
this.image = image;
}public JButton getButton() {
processBtn = new JButton("按钮");
processBtn.addActionListener(this);
return processBtn;
}@Override
protected void paintComponent(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
if (null != image) {
g2d.drawImage(image, 0, 0, image.getWidth(), image.getHeight(), null);
}if(resultImage != null) {
g2d.drawImage(resultImage, image.getWidth() + 10, 0, resultImage.getWidth(), resultImage.getHeight(), null);
}}public void process() {
BinaryFilter filter = new BinaryFilter();
resultImage = filter.process(this.image);
}@Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == processBtn) {
this.process();
this.repaint();
}
}public static void main(String[] args) {
File file = new File("resource/color.png");
try {
BufferedImage image = ImageIO.read(file);
ImagePanel imp = new ImagePanel(image);
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(imp, BorderLayout.CENTER);
frame.getContentPane().add(imp.getButton(), BorderLayout.SOUTH);
frame.setSize(1000, 600);
frame.setTitle("图像显示测试");
frame.setVisible(true);
} catch (IOException e) {
e.printStackTrace();
}}}
文章图片
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