Source Code : How to compare images for similarity using java

How to compare images for similarity using java

1 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 new image is given. I started my project with googling "How to compare images using java" and I got some good articles on finding the similarity of two images. Almost all of them were based on four basic steps, they are:

1.Locating the Region of Interest (Where the Objects appear in the given image),
2.Re-sizing the ROIs in to a common size,
3.Substracting ROIs,
4.Calculating the Black and White Ratio of the resultant image after subtraction.Though this sounds as a good algorithm to compare images, it takes a considerable amount of time after implementing it using JAI in my project. Therefore I have to find an alternate method of doing it.

Any suggestions?
java image image-processing
share|improve this question asked Dec 19 '11 at 21:39
sum2000
540620 
 
    
 Have you thought of using OpenCV? stackoverflow.com/questions/2037579/java-
 
down vote  Depending on how different the images are, you could do something like this (pseudocode). It's very primitive, but should be pretty efficient. You could speed it up by taking random or patterned pixels instead of every one.

for x = 0 to image.size:
    for y = 0 to image.size:
        diff += abs(image1.get(x,y).red - image2.get(x,y).red)
        diff += abs(image1.get(x,y).blue - image2.get(x,y).blue)
        diff += abs(image1.get(x,y).green - image2.get(x,y).green)
    end
end

return ((float)(diff)) / ( x * y * 3)share|improve this answer answered Dec 19 '11 at
 
    
 does this really give enough precision?? –  sum2000 Dec 19 '11 at 21:45 
   
 Well I don't think it's precision you're looking for, but accuracy. For example, if you take an image and offset it by 3 pixels down and left, this will show that the images are almost nothing alike. But then you have to ask yourself, should it? – 

No problem. We won't show you that ad again. Why didn't you like it?UninterestingMisleadingOffensiveRepetitiveOops! I didn't mean to do this.

 

down vote      **// This API will compare two image file //
// return true if both image files are equal else return false//**
public static boolean compareImage(File fileA, File fileB) {       
    try {
        // take buffer data from botm 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();
        // compare data-buffer objects //
        if(sizeA == sizeB) {
            for(int i=0; i                if(dbA.getElem(i) != dbB.getElem(i)) {
                    return false;
                }
            }
            return true;
        }
        else {
            return false;
        }
    }
    catch (Exception e) {
        System.out.println("Failed to compare image files ...");
        return  false;
    }
}