Your explanation on how you plan to keep the data anonymised sounds good. I also love that you’re using existing cameras, I recently observed as a large it-consultancy piloted their multi-camera solution with a large Finnish grocery store chain and got rather poor results, mainly due to cost and amount work being too high when compared to the results.

This also instantly reminded me of the time I used to work in large thrift shop. Everyday the owner would count the daily visitors and compare it and the daily sales number to factors such as the amount of tables, changes in floor plans, amount of new items etc. He would have loved something like this.

Good luck with your product!