how to compare between two images?

I'm working on my project, and now i'm taking a real time video for detecting fire within a bounding box, and then crop the detected object within the bounding box. After that two images will be taken from the video, then edge algorithm will be applied. After that i need to compare between the two images. i'm done till the edge detection part, i need to compare the edges to check if there is any change. What algorithm i have to use to compare?? please help me

Answer 1

[Azzi Abdelmalek]

A==B  % compare image A and image B