Java实现图片去噪和灰度的类

用于实现对图片去噪和灰度化。

package org.eye;

import java.awt.Color;
import java.awt.color.ColorSpace;
import java.awt.image.BufferedImage;
import java.awt.image.ColorConvertOp;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;

public class ClearImageHelper {
/**
*
* @param sfile
* 需要去噪的图像
* @param destDir
* 去噪后的图像保存地址
* @throws IOException
*/
public static void cleanImage(File sfile, String destDir)throws IOException{
File destF = new File(destDir);
if (!destF.exists()){
destF.mkdirs();
}

BufferedImage bufferedImage = ImageIO.read(sfile);
int h = bufferedImage.getHeight();
int w = bufferedImage.getWidth();

// 灰度化
int[][] gray = new int[w][h];
for (int x = 0; x < w; x++){
for (int y = 0; y < h; y++){
int argb = bufferedImage.getRGB(x, y);
// 图像加亮（调整亮度识别率非常高）
int r = (int) (((argb >> 16) & 0xFF) * 1.1 + 30);
int g = (int) (((argb >> 8) & 0xFF) * 1.1 + 30);
int b = (int) (((argb >> 0) & 0xFF) * 1.1 + 30);
if (r >= 255){
r = 255;
}
if (g >= 255){
g = 255;
}
if (b >= 255){
b = 255;
}
gray[x][y] = (int) Math.pow((Math.pow(r, 2.2) * 0.2973 + Math.pow(g, 2.2)* 0.6274 + Math.pow(b, 2.2) * 0.0753), 1 / 2.2);
}
}

// 二值化
int threshold = ostu(gray, w, h);
BufferedImage binaryBufferedImage = new BufferedImage(w, h,BufferedImage.TYPE_BYTE_BINARY);
for (int x = 0; x < w; x++){
for (int y = 0; y < h; y++){
if (gray[x][y] > threshold){
gray[x][y] |= 0x00FFFF;
} else{
gray[x][y] &= 0xFF0000;
}
binaryBufferedImage.setRGB(x, y, gray[x][y]);
}
}

// 矩阵打印
for (int y = 0; y < h; y++){
for (int x = 0; x < w; x++){
if (isBlack(binaryBufferedImage.getRGB(x, y))){
System.out.print("*");
} else{
System.out.print(" ");
}
}
System.out.println();
}
ImageIO.write(binaryBufferedImage, "jpg", new File(destDir, sfile.getName()));
}

public static boolean isBlack(int colorInt){
Color color = new Color(colorInt);
if (color.getRed() + color.getGreen() + color.getBlue() <= 300){
return true;
}
return false;
}

public static boolean isWhite(int colorInt){
Color color = new Color(colorInt);
if (color.getRed() + color.getGreen() + color.getBlue() > 300){
return true;
}
return false;
}

public static int isBlackOrWhite(int colorInt){
if (getColorBright(colorInt) < 30 || getColorBright(colorInt) > 730){
return 1;
}
return 0;
}

public static int getColorBright(int colorInt){
Color color = new Color(colorInt);
return color.getRed() + color.getGreen() + color.getBlue();
}

public static int ostu(int[][] gray, int w, int h){
int[] histData = new int[w * h];
// Calculate histogram
for (int x = 0; x < w; x++){
for (int y = 0; y < h; y++){
int red = 0xFF & gray[x][y];
histData[red]++;
}
}

// Total number of pixels
int total = w * h;

float sum = 0;
for (int t = 0; t < 256; t++)
sum += t * histData[t];

float sumB = 0;
int wB = 0;
int wF = 0;

float varMax = 0;
int threshold = 0;

for (int t = 0; t < 256; t++){
wB += histData[t]; // Weight Background
if (wB == 0)
continue;

wF = total - wB; // Weight Foreground
if (wF == 0)
break;

sumB += (float) (t * histData[t]);

float mB = sumB / wB; // Mean Background
float mF = (sum - sumB) / wF; // Mean Foreground

// Calculate Between Class Variance
float varBetween = (float) wB * (float) wF * (mB - mF) * (mB - mF);

// Check if new maximum found
if (varBetween > varMax){
varMax = varBetween;
threshold = t;
}
}

return threshold;
}
//图片灰度，黑白
public static void gray(String srcImageFile, String destImageFile) {
try {
BufferedImage src = ImageIO.read(new File(srcImageFile));
ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
ColorConvertOp op = new ColorConvertOp(cs, null);
src = op.filter(src, null);
ImageIO.write(src, "JPEG", new File(destImageFile));
} catch (IOException e) {
e.printStackTrace();
}
}

public static void main(String[] args) throws IOException{
/*File testDataDir = new File("testdata");
final String destDir = testDataDir.getAbsolutePath()+"/tmp";
for (File file : testDataDir.listFiles()){
cleanImage(file, destDir);
}*/
File testDataDir = new File("D:\\tmp\\3VG5B.jpg");//去噪
String destDir ="D:\\tmp\\tmp";
cleanImage(testDataDir, destDir);
//gray("D:\\tmp\\3VG5B.jpg","D:\\tmp\\3VG5B1.jpg");//灰度化
}
}