How to compare images for similarity using java

Question

Recently I got an opportunity to work with Image Processing Technologies as a part of one of my projects and my task was to find matching images from an image store when a n

Answer 1

This API will compare two image file and return the percentage of similarity

public float compareImage(File fileA, File fileB) {

    float percentage = 0;
    try {
        // take buffer data from both image files //
        BufferedImage biA = ImageIO.read(fileA);
        DataBuffer dbA = biA.getData().getDataBuffer();
        int sizeA = dbA.getSize();
        BufferedImage biB = ImageIO.read(fileB);
        DataBuffer dbB = biB.getData().getDataBuffer();
        int sizeB = dbB.getSize();
        int count = 0;
        // compare data-buffer objects //
        if (sizeA == sizeB) {

            for (int i = 0; i < sizeA; i++) {

                if (dbA.getElem(i) == dbB.getElem(i)) {
                    count = count + 1;
                }

            }
            percentage = (count * 100) / sizeA;
        } else {
            System.out.println("Both the images are not of same size");
        }

    } catch (Exception e) {
        System.out.println("Failed to compare image files ...");
    }
    return percentage;
}