From time to time, some people come here and ask for help (or better, code) to solve some of the most difficult research problems in computer vision. Problems that have not been resolved by the most famous scientists and scientists. Sometimes they ask for the algorithms they saw in SF films. Then they leave disappointment because OpenCV is not friendly enough.
Now, seriously, if you work at PhD Image Processing, working on some ingenious project, you don't need advice here. And if you do not, the chance to do so is very low.
What you can do with reasonable resources and accuracy is to keep track of the people in the store: use a moving average background subtracter (available in OpenCV) to determine what the empty store looks like, and subtract this background from each frame to see the items that come in and disappear. You can extract them using blob analisys lib. The Kalman filter (or a simpler tracker) helps you keep track of moving objects.
Good luck
source share