[java]图片彩色转灰色
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2024-02-16 23:14:04
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灰度化处理有多种处理方式:
1.分量法
2.最大法
3.平均法
4.加权平均法
下面采用的是对R、G、B分量进行加权平均的算法:
0.2989R+ 0.5870G + 0.1140B
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.*;
public class ToGray {
public static void main(String args[]) throws IOException {
BufferedImage imgIn = ImageIO.read(new File("test.jpg"));
int inWith = imgIn.getWidth();
int inHeight = imgIn.getHeight();
int imx = imgIn.getMinX();
int imy = imgIn.getMinY();
for(int i = imx; i < inWith; i++){
for(int j = imy; j < inHeight; j++){
int pixel = imgIn.getRGB(i, j); //
int[] rgb = new int[3];
rgb[0] = (pixel & 0xff0000) >> 16; //r
rgb[1] = (pixel & 0xff00) >> 8; //g
rgb[2] = (pixel & 0xff); //b
//gray = r * 0.299 + g * 0.578 + b* 0.114
float[] r = new float[3];
r[0] = (float) (rgb[0]*0.299);
r[1] = (float) (rgb[0]*0.578);
r[2] = (float) (rgb[0]*0.114);
int gray = (int) (r[0] + r[1] + r[2]);
imgIn.setRGB(i, j, (gray << 16) | (gray << 8) | gray);
}
}
writeToFile(imgIn, "png", new File("out.png"));//写到文件
}
public static void writeToFile(BufferedImage image, String format, File file)
throws IOException {
if (!ImageIO.write(image, format, file)) {
throw new IOException("Could not write an image of format " + format + " to " + file);
}
}
}
处理前
处理后
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