Comparing image similarity using OpenCV in Java

Question

How can I compare two images similarity in Java using OpenCV. I must mention that those images may differ by angle, luminosity, etc. I'm not interested in comparing identical images. For example:

After processing these 2 images, I want to know that they contain the same object, or that they look 70% similar

Answer 1

This is possible in Java, using ASIFT, implemented in OpenImaj library. Example here

Asift extacts local features from a image and then it's used a matcher in order to detect similar features.

ASIFT online demo here: http://demo.ipol.im/demo/my_affine_sift/