java - 在java中为缓冲图像提供颜色

Question

我有一个看起来像这样的缓冲图像。

如何给它上色？我是java图像处理的新手，任何帮助将不胜感激。这是生成此图片的代码示例。

   public BufferedImage getDifferenceImage(BufferedImage img1, BufferedImage img2) {
    int width1 = img1.getWidth(); // Change - getWidth() and getHeight() for BufferedImage
    int width2 = img2.getWidth(); // take no arguments
    int height1 = img1.getHeight();
    int height2 = img2.getHeight();
    if ((width1 != width2) || (height1 != height2)) {
        System.err.println("Error: Images dimensions mismatch");
        System.exit(1);
    }

    // NEW - Create output Buffered image of type RGB
    BufferedImage outImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

    // Modified
    long diff;
    int result; // Stores output pixel
    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); // Change
            diff += Math.abs(g1 - g2);
            diff += Math.abs(b1 - b2);
            diff /= 255; // Change - Ensure result is between 0 - 255
            // Make the difference image gray scale
            // The RGB components are all the same
            result = (diff << 16) | (diff << 8) | diff;
            outImg.setRGB(j, i, result); // Set result
        }
    }

    // Now return
    return outImg;
}

Answer 1

尝试更改计算颜色之间差异的代码，不要将每个颜色 channel 设置为相同并生成灰度，而是尝试将每个颜色 channel 设置为各自的差异，而不是将差异相加在每个颜色 channel 中。换句话说，试试这个:

// Modified - Changed to int as pixels are ints
int rDiff, gDiff, bDiff;
int result; // Stores output pixel
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;
        rDiff = Math.abs(r1 - r2); // Change
        gDiff = Math.abs(g1 - g2);
        bDiff = Math.abs(b1 - b2);
        result = (rDiff << 16) | (gDiff << 8) | bDiff;
        outImg.setRGB(j, i, result); // Set result
    }
}

<小时/>

编辑 - 2014 年 8 月 1 日

您提到，如果相应点的两个像素之间存在任何差异，我们应该将此颜色设置为黄色(或紫色/洋红色)。我们可以很容易地做到这一点。只需计算所有 channel 之间的附加差异，如果它不等于 0，则将输出颜色设置为黄色(或紫色/洋红色)。否则，只需保持颜色不变即可。我还假设如果没有差异，您将希望保持图像 1 中的像素相同。如果您想保持图像 2 的像素相同，只需更改代码中的变量即可。换句话说:

// Modified - Changed to int as pixels are ints
int diff;
int result; // Stores output pixel
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); // Change
        diff += Math.abs(g1 - g2);
        diff += Math.abs(b1 - b2);

        // Check for any differences
        if (diff != 0) {
           r1 = 255;  // If there is, set output to yellow
           g1 = 255;
           b1 = 0;
           /* // Use this for purple / magenta
           r1 = 255;
           g1 = 0;
           b1 = 255; */
        }

        // If there are no differences, r1, g1 and b1
        // will contain the original colours for image 1
        // If there is, then r1, g1, b1 will be set to yellow

        // Set output pixel
        result = (r1 << 16) | (g1 << 8) | b1;
        outImg.setRGB(j, i, result); // Set result
    }
}