An image sensor is positioned such that a field-of-view of the image sensor encompasses at least a portion of a structure configured to store items. The image sensor generates angled-view images of the items stored on the structure. A tracking subsystem determines that a person has interacted with the structure and receives image frames of the angled-view images. The tracking subsystem determines that the person interacted with a first item stored on the structure. A first image is identified associated with a first time before the person interacted with the first item, and a second image is identified associated with a second time after the person interacted with the first item. If it is determined, based on a comparison of the first and second images, that the item was removed from the structure, the first item is assigned to the person.