1. A method of managing states of visual models stored in a data store configured to retain a plurality of records corresponding to a plurality of items of merchandise, the method comprising: acquiring, by use of an imager device operatively coupled to a self-checkout system, an image generated during a merchandise checkout process performed at the self-checkout system, the acquired image depicting an item of merchandise when the item is located within a field of view of the imager device during the merchandise checkout process; obtaining a product code by use of the self-checkout system to read, during the merchandise checkout process, the product code from an optical code that visually encodes the product code and is borne by the item of merchandise so as to identify the item based on the product code; extracting one or more geometric point features from the acquired image of the item; accessing a record corresponding to the item by requesting from the data store the record having a match with the product code, the record including a visual model of the item and a state of the visual model, the visual model comprising: a stored image of the item, and one or more stored geometric point features extracted from one or more previously acquired images of the item; determining from the record whether the state of the visual model indicates the visual model is appropriate for use in adding items to a transaction in connection with the merchandise checkout process; in response to the state indicating that the visual model is appropriate for use in adding items to a transaction in connection with the merchandise checkout process, performing visual object recognition based on a comparison between the one or more geometric point features extracted from the acquired image of the item and the one or more stored geometric point features of the visual model to confirm that the item is actually represented by the record and has been correctly identified by the product code read from the optical code during the merchandise checkout process; and in response to the state indicating that the visual model is not appropriate for use in adding items to a transaction in connection with the merchandise checkout process, automatically updating the record to incorporate the one or more geometric point features extracted from the acquired image and to modify the state of the visual model to indicate that the visual model is appropriate for use in adding items to a transaction.