US Patent 10963834 Maintaining accurate cart-state using auto-generated sensor data

This disclosure describes techniques for utilizing sensor data to determine the results of events within a system. Upon receiving sensor data indicative of an event, the sensor data is analyzed to determine a result of the event. For instance, a user may identified upon entry to a facility, may pick items from shelves in the facility, and may be identified upon exit. Contents of a virtual shopping cart of the user may be maintained based on analysis of the sensor data as the user picks the items. When a user exits, a payment instrument of the user may be charged for a cost of the items and a receipt may be sent to a device of the user. A state-invariant time, representing a time before which all events have been processed, may be maintained such that no shopping sessions are finalized prior to the state-invariant time to avoid mistaken charges.