Startup Idea: Retail Visitor Tracking Software

Startup idea to develop a robust software for retail businesses to accurately calculate and track the number of customers entering and exiting the store.

We have issues keeping track of sales with software at times. We have a counter that keeps track of the visitors we have in the store, yet the software is not working probably. Maybe have software that is able to calculate the amount of people that come in and out the store. I would pay for this software.