java - Filter difference between 2 images? -

i trying filter out difference between 2 images (screenshots). unfortunately have absolutely no experience in java , images , have no real idea for.

are there ready-to-use classes that?

what expecting like:

image imga = new (pathtoa);   // image instance 500kb image imgb = new (pathtob);   // image instance 500kb image imgc = imagefilter.filterdifference(imga, imgb);   // difference between imga , imgb , therefore instance 20kb 

edit:

example: anyway, mean difference visual difference between images (screenshots). if have 1 screenshot 5 icons in folder , screenshot 1 icon more, want imgc show new icon.

edit 2:

clarification: want difference between 2 screenshots in new image.

edit 3:

some kind of code 1 (code not work):

private bufferedimage getimagedifference(bufferedimage img1, bufferedimage img2) {     if (img1.getwidth() == img2.getwidth() && img1.getheight() == img2.getheight()) {         bufferedimage img3 = new bufferedimage(img1.getheight(), img1.getwidth(), img1.gettype());         (int x = 0; x < img1.getwidth(); x++) {             (int y = 0; y < img1.getheight(); y++) {                 if (img1.getrgb(x, y) != img2.getrgb(x, y))                     //return false;                     img3.setrgb(x, y, img2.getrgb(x, y));             }             return img3;         }     } else {         return false;     } } 

since interested in screenshots can expect difference image minimal. true small time intervals it's highly uncertain larger. imagine desktop when using application , in few seconds while continuing use same application , on other hand case use different application. parts explains guess file sizes provide images. difference image saved in greyscale format this.

i don't know if there ready library this. suggest (simple) approach kick point:

1. just subtract 2 images and
2. threshold difference image:
3. a) keep differences above value.
4. b) keep areas have amount of neighboring pixels differing (this leave out isolated pixel noise)
5. you can further process difference image depending on needs.

not java specific solution guess. if don't have idea can start reading bufferedimage example