Frame differencing
Frame differencing is one of the simplest techniques that can be used to identify the moving parts in a video. Intuitively, in most applications this is where the fun part exists. If we have a video of a runner, we probably want to analyze the runner as they run and not the background images. When we watch a movie, we focus mostly on the characters in the forefront while they talk and do things. We don't tend to focus on the boring picture frames in the background.
Occasionally, you get the one-off geek that finds a problem in a movie hidden in this background, as we saw a couple of times in recent episodes of Game of Thrones when people found a cup of Starbucks in the background, but this is the exception rather than the rule.
When we are looking at a live video stream, the differences between consecutive frames captured from the stream gives us a lot of information. Let's see how we can take the differences between consecutive frames and display...