US Patent 9120621 Verifying bin content in an automated materials handling facility

This disclosure describes a device and system for verifying the content of items in a bin of an inventory holder within a materials handling facility. In some implementations, a bin content verification apparatus may be positioned within the materials handling facility and configured to capture images of inventory holders that include bins as the inventory holders are moved past the apparatus by mobile drive units. The images may be processed to determine whether the content included in the bins has changed since the last time images of the bins were captured. A determination may also be made as to whether a change to the bin content was expected and, if so, if the determined change corresponds with the expected change.