这篇文章介绍了如何以文本的形式来展示图片,以前做过这个程序,后来找不到了,重新记录一下.
import net.coobird.thumbnailator.Thumbnails;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.*;
import java.nio.charset.StandardCharsets;
public class ImageUtil {
public static void main(String[] args) throws IOException {
String fromPic = "C:\\Users\\Public\\Pictures\\Sample Pictures\\507597_240.jpg";
String toTxt = "d:\\test5.txt";
BufferedImage bufferedImage = ImageIO.read(new File(fromPic));
// 1.压缩图片
BufferedImage compactImage = Thumbnails.of(bufferedImage).size(100, 500).asBufferedImage();
// 2.灰度化
BufferedImage grayImage = grayingImage(compactImage);
// 3.二值化
BufferedImage binaryImage = binaryImage(grayImage);
// 4.输出到txt文本
writeToTxt(binaryImage, toTxt);
/*保存图片
File newFile = new File("d:\\test5.jpg");
ImageIO.write(binaryImage, "jpg", newFile);*/
}
/**
* 灰度化图片
* @param bufferedImage 原图片
* @return 灰度化之后的图片
*/
private static BufferedImage grayingImage(BufferedImage bufferedImage) {
BufferedImage grayImage = new BufferedImage(bufferedImage.getWidth(), bufferedImage.getHeight(),
BufferedImage.TYPE_BYTE_GRAY);
for (int i = 0; i < bufferedImage.getWidth(); i++) {
for (int j = 0; j < bufferedImage.getHeight(); j++) {
int color = bufferedImage.getRGB(i, j);
grayImage.setRGB(i, j, color);
}
}
return grayImage;
}
/**
* 二值化图片
* @param bufferedImage 原图片
* @return 二值化后的图片
*/
private static BufferedImage binaryImage(BufferedImage bufferedImage) {
BufferedImage grayImage = new BufferedImage(bufferedImage.getWidth(), bufferedImage.getHeight(), bufferedImage.getType());
int threshold = getMeanThreshold(bufferedImage);
for (int i = 0; i < bufferedImage.getWidth(); i++) {
for (int j = 0; j < bufferedImage.getHeight(); j++) {
int color = bufferedImage.getRGB(i, j);
int r = (color >> 16) & 0xff;
int g = (color >> 8) & 0xff;
int b = color & 0xff;
int gray = (int) (0.3 * r + 0.59 * g + 0.11 * b);
if (gray > threshold) {
grayImage.setRGB(i, j, 0xFFFFFF);
}
else {
grayImage.setRGB(i, j, 0);
}
}
}
return grayImage;
}
/**
* 获取图片的阀值,采用基于灰度平均值的阈值
* @param bufferedImage 原图片
* @return 二值化的阈值
*/
private static int getMeanThreshold(BufferedImage bufferedImage) {
int w = bufferedImage.getWidth();
int h = bufferedImage.getHeight();
int num = 0;
int sum = 0;
for(int i=0; i<w; i++) {
for(int j = 0; j < h; j++) {
int color = bufferedImage.getRGB(i, j);
int r = (color >> 16) & 0xff;
int g = (color >> 8) & 0xff;
int b = color & 0xff;
int gray = (int) (0.3 * r + 0.59 * g + 0.11 * b);
sum += gray;
num += 1;
}
}
// 测试表明,阀值取平均值的1.2倍效果最好。
int threshold = sum / num;
if(threshold * 1.2 < 255) {
threshold = (int)(1.2 * sum / num);
}
System.out.println("width: " + w + " height: " + h + " threshold: " + threshold);
return threshold;
}
/**
* 输出 0,1 TXT文本
*/
public static void writeToTxt(BufferedImage bufferedImage, String toSaveFilePath) {
File file = new File(toSaveFilePath);
try {
Writer writer = new OutputStreamWriter(new FileOutputStream(file, true), StandardCharsets.UTF_8);
StringBuilder builder = new StringBuilder();
for (int j = 0; j < bufferedImage.getHeight(); j++) {
for(int i = 0; i < bufferedImage.getWidth(); i++) {
int color = bufferedImage.getRGB(i, j);
if(color == -1) {
builder.append(" ");
}
else {
builder.append("0");
}
}
builder.append("\r\n");
}
writer.write(builder.toString());
writer.close();
}
catch (Exception e) {
e.printStackTrace();
}
}
}