java将图片白底变成透明[转]

公司项目需求需要将指纹采集仪器上传上来的图片与手写签名合成在一起，但是采集到的指纹图片带有白色的背景，合成之后会将签名给覆盖，所以需要将指纹图片的白色背景变成透明！

 

代码

package com.bobo.code.web.controller;

import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.regex.Pattern;

public class RemoveBackground  {
    public static int color_range = 210;
    public static Pattern pattern = Pattern.compile("[0-9]*");

    public static boolean isNo(String str) {
        return pattern.matcher(str).matches();
    }

    public static void convert(String inputFilePath) {
        File inputFile = new File(inputFilePath);
        if (!inputFile.exists() || !inputFile.isFile()) {
            System.out.println("Invalid input file path: " + inputFilePath);
            return;
        }

        try {
            BufferedImage image = ImageIO.read(new File(inputFilePath));
            ImageIcon imageIcon = new ImageIcon(image);
            BufferedImage bufferedImage = new BufferedImage(
                    imageIcon.getIconWidth(), imageIcon.getIconHeight(),
                    BufferedImage.TYPE_4BYTE_ABGR);
            Graphics2D g2D = (Graphics2D) bufferedImage.getGraphics();
            g2D.drawImage(imageIcon.getImage(), 0, 0,
                    imageIcon.getImageObserver());
            int alpha ;
            for (int j1 = bufferedImage.getMinY(); j1 < bufferedImage
                    .getHeight(); j1++) {
                for (int j2 = bufferedImage.getMinX(); j2 < bufferedImage
                        .getWidth(); j2++) {
                    int rgb = bufferedImage.getRGB(j2, j1);
                    if (colorInRange(rgb))
                        alpha = 0;
                    else
                        alpha = 255;
                    rgb = (alpha << 24) | (rgb & 0x00ffffff);
                    bufferedImage.setRGB(j2, j1, rgb);
                }
            }
            g2D.drawImage(bufferedImage, 0, 0, imageIcon.getImageObserver());
            // 生成图片为PNG
            String outputFilePath = inputFile.getParent() + "/target.png";
            ImageIO.write(bufferedImage, "png", new File(outputFilePath));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static boolean colorInRange(int color) {
        int red = (color & 0xff0000) >> 16;
        int green = (color & 0x00ff00) >> 8;
        int blue = (color & 0x0000ff);
        if (red >= color_range && green >= color_range && blue >= color_range)
            return true;
        return false;
    }



    public static void main(String[] args) throws Exception {
        convert("C:\\SoftWorkspace\\SnipasteWorkspace\\abc\\src.png");
    }
}

 

效果

原图 src.png

目标图 target.png  (透明)