java - 突出显示图像之间的差异

Question

我应该修改此图像比较代码以突出显示/指出两个图像之间的差异。有没有办法修改此代码以突出显示图像中的差异。如果没有关于如何进行的任何建议，我们将不胜感激。

 int width1 = img1.getWidth(null);
            int width2 = img2.getWidth(null);
            int height1 = img1.getHeight(null);
            int height2 = img2.getHeight(null);
            if ((width1 != width2) || (height1 != height2)) {
                System.err.println("Error: Images dimensions mismatch");
                System.exit(1);
            }
            long diff = 0;
            for (int i = 0; i < height1; i++) {
                for (int j = 0; j < width1; j++) {
                    int rgb1 = img1.getRGB(j, i);
                    int rgb2 = img2.getRGB(j, i);
                    int r1 = (rgb1 >> 16) & 0xff;
                    int g1 = (rgb1 >> 8) & 0xff;
                    int b1 = (rgb1) & 0xff;
                    int r2 = (rgb2 >> 16) & 0xff;
                    int g2 = (rgb2 >> 8) & 0xff;
                    int b2 = (rgb2) & 0xff;
                    diff += Math.abs(r1 - r2);
                    diff += Math.abs(g1 - g2);
                    diff += Math.abs(b1 - b2);
                }
            }
            double n = width1 * height1 * 3;
            double p = diff / n / 255.0;
            return (p * 100.0);

Answer 1

这个解决方案对我有用。它突出了差异，并且在我尝试过的方法中具有最佳性能。 (假设:图像大小相同。此方法尚未使用透明胶片进行测试。)

比较 1600x860 PNG 图像 50 次的平均时间(在同一台机器上):

• JDK7 ~178 毫秒
• JDK8 ~139 毫秒

有没有人有更好/更快的解决方案？

public static BufferedImage getDifferenceImage(BufferedImage img1, BufferedImage img2) {
    // convert images to pixel arrays...
    final int w = img1.getWidth(),
            h = img1.getHeight(), 
            highlight = Color.MAGENTA.getRGB();
    final int[] p1 = img1.getRGB(0, 0, w, h, null, 0, w);
    final int[] p2 = img2.getRGB(0, 0, w, h, null, 0, w);
    // compare img1 to img2, pixel by pixel. If different, highlight img1's pixel...
    for (int i = 0; i < p1.length; i++) {
        if (p1[i] != p2[i]) {
            p1[i] = highlight;
        }
    }
    // save img1's pixels to a new BufferedImage, and return it...
    // (May require TYPE_INT_ARGB)
    final BufferedImage out = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
    out.setRGB(0, 0, w, h, p1, 0, w);
    return out;
}

用法:

import javax.imageio.ImageIO;
import java.io.File;

ImageIO.write(
        getDifferenceImage(
                ImageIO.read(new File("a.png")),
                ImageIO.read(new File("b.png"))),
        "png",
        new File("output.png"));

Some inspiration...