简单的图像二值化处理

package template;

import org.junit.Test;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

/**
 * 图像二值化
 *
 * @author duxuefu
 * 2018/9/10 13:46
 */
public class ImageBinaryzation {
    @Test
    public void binaryzation() {
        // 原图
        String from = "d:/image/5b3b4f8fN871fbc51.jpg";
        // 二值化后图片
        String tob = "d:/image/colatob.png";
        try {
            BufferedImage bufferedImage = ImageIO.read(new File(from));
            BufferedImage binaryBufferedImage = new BufferedImage(bufferedImage.getWidth(), bufferedImage.getHeight(), BufferedImage.TYPE_INT_BGR);
            // 抽象成线条
//            fuseLine(bufferedImage, binaryBufferedImage);
            // 抽象成色块
            fuseArea(bufferedImage, binaryBufferedImage);
            ImageIO.write(binaryBufferedImage, "png", new File(tob));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 抽象成色块
     *
     * @param bufferedImage    原图
     * @param newBufferedImage 处理后图片
     */
    private void fuseArea(BufferedImage bufferedImage, BufferedImage newBufferedImage) {
        int width = bufferedImage.getWidth();
        int height = bufferedImage.getHeight();
        System.out.println("----------------------------");
        int accumulate = 0;
        for (int i = 0; i < height; i++) {
            for (int j = 0; j < width; j++) {
                int pixel = bufferedImage.getRGB(j, i);
                int rx = (pixel & 0xff0000) >> 16;
                int gx = (pixel & 0xff00) >> 8;
                int bx = (pixel & 0xff);
                int gray = (rx + gx + bx) / 3;

                // TODO 阈值动态设定
                int highThreshold = 200;
                int lowThreshold = 70;
                gray += accumulate;
/*                if (rx > 250 && gx < 240 && bx < 240) {
                    newBufferedImage.setRGB(j, i, (255 << 16) + (0 << 8) + 0);
                } else */
                if ((rx + gx + bx) / 3 <= lowThreshold) {
                    // 处理黑色
                    newBufferedImage.setRGB(j, i, 0);
                    accumulate = 0;
                } else if ((rx + gx + bx) / 3 >= highThreshold) {
                    // 处理白色
                    newBufferedImage.setRGB(j, i, (255 << 16) + (255 << 8) + 255);
                    accumulate = 0;
                } else if (gray >= highThreshold) {
                    newBufferedImage.setRGB(j, i, (255 << 16) + (255 << 8) + 255);
                    accumulate = gray - 255;
                } else {
                    accumulate += gray;
                }
            }
            System.out.println();
        }
    }

    /**
     * 抽象成线条
     *
     * @param bufferedImage    原图
     * @param newBufferedImage 处理后图片
     */
    private void fuseLine(BufferedImage bufferedImage, BufferedImage newBufferedImage) {
        int width = bufferedImage.getWidth();
        int height = bufferedImage.getHeight();
        System.out.println("----------------------------");
        for (int i = 0; i < height; i++) {
            for (int j = 0; j < width; j++) {
                int pixel = bufferedImage.getRGB(j, i);
                int rx = (pixel & 0xff0000) >> 16;
                int gx = (pixel & 0xff00) >> 8;
                int bx = (pixel & 0xff);

                //灰化
                int gray = (rx + gx + bx) / 3;

                int fromx = j == 0 ? j : j - 1;
                int tox = j == bufferedImage.getWidth() - 1 ? j : j + 1;
                int fromy = i == 0 ? i : i - 1;
                int toy = i == bufferedImage.getHeight() - 1 ? i : i + 1;

                int max = 0; //最大值
                int average;//平均值
                int sum = 0;
                int count = 0;
                for (int m = fromx; m <= tox; m++) {
                    for (int n = fromy; n <= toy; n++) {
                        int pixelArea = bufferedImage.getRGB(m, n);
                        int grayArea = (((pixelArea & 0xff0000) >> 16) + ((pixelArea & 0xff00) >> 8) + (pixelArea & 0xff)) / 3;
                        if (grayArea > max) {
                            max = grayArea;
                        }
                        sum += grayArea;
                        count++;
//                        System.out.print(String.format("grayArea: %d", grayArea));
                    }
                }
                average = sum / count;
//                System.out.println(String.format("gray: %d sum: %d average: %d", gray, sum, average));
                // TODO 阈值动态设定
                if (rx > 250 && gx < 240 && bx < 240) {
                    newBufferedImage.setRGB(j, i, (255 << 16) + 0);
                } else if (gray >= average && average > 50) {
                    //System.out.println(sum + " " + average);
                    newBufferedImage.setRGB(j, i, (255 << 16) + (255 << 8) + 255);
                }
            }
        }
    }
}

原图

5b3b4f8fN871fbc51.jpg

fuseArea方法处理后的图片

colatob.png

fuseLine方法处理后的图片

colatob.png