US Patent 11373320 Detecting inventory changes by comparing image data

A camera with a field of view of a shelf may acquire images of items on the shelf at subsequent times. An analysis of each image yields a set of estimated locations of the items on the shelf. Based on a working volume of the shelf, a subset of valid estimated locations of the items at the shelf may be determined. Thereafter, a count of the items on the shelf at a particular time may be determined using the subset of valid estimated item locations. By comparing the count of items at the shelf at two subsequent times, a change in quantity of the items on the shelf may be determined. Interaction data may be generated in response to detecting the change in quantity of items at the shelf.