Moving object detection is like when you play hide and seek with your friends. You close your eyes and count to ten while your friends go hide. Then, when you open your eyes, you look around to see if you can find your friends hiding.
In computers, moving object detection is when a computer looks at pictures or videos and tries to find things that are moving in them. It's like the computer is playing hide and seek with the moving things in the pictures or videos.
The computer looks at each frame of the pictures or video and tries to find things that are moving by looking at the differences between them. Just like you can tell if your friends are moving if you see them in one spot and then see them in a different spot.
Once the computer finds the objects that are moving, it can do many things with that information. For example, it can track the movement of the objects, count how many are moving, or even sound an alarm if it thinks the objects might be dangerous.
So, moving object detection is like a game of hide and seek that computers play with pictures and videos to find things that are moving.